Dual chamber single actuator ink jet printing mechanism

ABSTRACT

An apparatus for ejecting fluids from a nozzle chamber is disclosed including a nozzle chamber having at least two fluid ejection apertures defined in the walls of the chamber; a moveable paddle vane located between the fluid ejection apertures; an actuator mechanism attached to the moveable paddle vane and adapted to move the paddle vane in a first direction so as to cause the ejection of fluid drops out of a first fluid ejection aperture and to further move the paddle vane in a second alternative direction so as to cause the ejection of fluid drops out of a second fluid ejection aperture. The actuator can comprise a thermal actuator having at least two heater elements with a first of the elements being actuated to cause the paddle vane to move in a first direction and a second heater element being actuated to cause the paddle vane to move in a second direction. The heater elements preferably have a high bend efficiency. The paddle vane and the actuator can be joined at a fulcrum pivot point, the fulcrum pivot point having a thinned portion of the nozzle chamber wall. The actuator can include one end fixed to a substrate and a second end containing a bifurcated tongue having two leaf portions on each end of the bifurcated tongue the leaf portions interconnecting to a corresponding side of the paddle with the tongue such that, upon actuation of the actuator, one of the leaf portions pulls on the paddle end.

FIELD OF THE INVENTION

The present invention relates to the field of inkjet printing and inparticular discloses a dual chamber single actuator inkjet printer.

BACKGROUND OF THE INVENTION

Many different types of printing have been invented, a large number ofwhich are presently in use. The known forms of print have a variety ofmethods for marking the print media with a relevant marking media.Commonly used forms of printing include offset printing, laser printingand copying devices, dot matrix type impact printers, thermal paperprinters, film recorders, thermal wax printers, dye sublimation printersand ink jet printers both of the drop on demand and continuous flowtype. Each type of printer has its own advantages and problems whenconsidering cost, speed, quality, reliability, simplicity ofconstruction and operation etc.

In recent years, the field of ink jet printing, wherein each individualpixel of ink is derived from one or more ink nozzles has becomeincreasingly popular primarily due to its inexpensive and versatilenature.

Many different techniques on ink jet printing have been invented. For asurvey of the field, reference is made to an article by J Moore,“Non-Impact Printing: Introduction and Historical Perspective”, OutputHard Copy Devices, Editors R Dubeck and S Sherr, pages 207-220 (1988).

Ink Jet printers themselves come in many different types. Theutilization of a continuous stream ink in ink jet printing appears todate back to at least 1929 wherein U.S. Pat. No. 1,941,001 by Hanselldiscloses a simple form of continuous stream electrostatic ink jetprinting.

U.S. Pat. 3,596,275 by Sweet also discloses a process of a continuousink jet printing including the step wherein the ink jet stream ismodulated by a high frequency electro-static field so as to cause dropseparation. This technique is still utilized by several manufacturersincluding Elmjet and Scitex (see also U.S. Pat, No. 3,373,437 by Sweetet al)

Piezo-electric ink jet printers are also one form of commonly utilizedink jet printing device. Piezo-electric systems are disclosed by Kyseret. al. in U.S. Pat. No. 3,946,398 (1970) which utilizes a diaphragmmode of operation, by Zolten in U.S. Pat. No. 3,683,212 (1970) whichdiscloses a squeeze mode of operation of a piezo electric crystal,Stemme in U.S. Pat. No. 3,747,120 (1972) discloses a bend mode ofpiezo-electric operation, Howkins in U.S. Pat. No. 4,459,601 discloses aPiezo electric push mode actuation of the ink jet stream and Fischbeckin U.S. Pat. No. 4,584,590 which discloses a sheer mode type ofpiezo-electric transducer element.

Recently, thermal ink jet printing has become an extremely popular formof ink jet printing. The ink jet printing techniques include thosedisclosed by Endo et al in GB 2007162 (1979) and Vaught et al in U.S.Pat. No. 4490728. Both the aforementioned references disclosed ink jetprinting techniques rely upon the activation of an electrothermalactuator which results in the creation of a bubble in a constrictedspace, such as a nozzle, which thereby causes the ejection of ink froman aperture connected to the confined space onto a relevant print media.Printing devices utilizing the electro-thermal actuator are manufacturedby manufacturers such as Canon and Hewlett Packard.

As can be seen from the foregoing, many different types of printingtechnologies are available. Ideally, a printing technology should have anumber of desirable attributes. These include inexpensive constructionand operation, high speed operation, safe and continuous long termoperation etc. Each technology may have its own advantages anddisadvantages in the areas of cost, speed, quality, reliability, powerusage, simplicity of construction operation, durability and consumables.

In any inkjet printing arrangement, especially where page widthprintheads are being constructed and utilized, it is important tominimize the size of the structure of each ejection nozzle. As theinkjet nozzles may be constructed in the form of multiple nozzles at atime on for example, silicon wafer, by minimizing the size of eachnozzle, it is possible to fit more nozzles and hence more printheads ona single silicon wafer. It is therefore advantageous to provide for anarrangement that is of a compact size and utilizes low energy levels soas to minimize the energy requirements in the actuation of inkjetprintheads.

SUMMARY OF THE INVENTION

It is an object of the present invent to provide an efficient dualchamber single vertical actuator inkjet printer.

In accordance with a first aspect of the present invention, there isprovided an apparatus for ejecting fluids from a nozzle chambercomprising a nozzle chamber having at least two fluid ejection aperturesdefined in the walls of the chamber; a moveable paddle vane locatedbetween the fluid ejection apertures; an actuator mechanism attached tothe moveable paddle vane and adapted to move the paddle vane in a firstdirection so as to cause the ejection of fluid drops out of a firstfluid ejection aperture and to further move the paddle vane in a secondalternative direction so as to cause the ejection of fluid drops out ofa second fluid ejection aperture.

The actuator can comprise a thermal actuator having at least two heaterelements with a first of the elements being actuated to cause the paddlevane to move in a first direction and a second heater element beingactuated to cause the paddle vane to move in a second direction. Theheater elements preferably have a high bend efficiency wherein the bendefficiency is defined as the youngs modulus times the coefficient ofthermal expansion divided by the density and by the specific heatcapacity.

The heater elements can be arranged on opposite sides of a central arm,the central arm having a low thermal conductivity.

The paddle vane and the actuator can be joined at a fulcrum pivot point,the fulcrum pivot point comprising a thinned portion of the nozzlechamber wall. The actuator can include one end fixed to a substrate anda second end containing a bifurcated tongue having two leaf portions oneach end of the bifurcated tongue, the leaf portions interconnecting toa corresponding side of the paddle with the tongue such that, uponactuation of the actuator, one of the leaf portions pulls on the paddleend.

The apparatus can further comprise a fluid supply channel connecting thenozzle chamber with a fluid supply for supplying fluid to the nozzlechamber, the connection being in a wall of the chamber substantiallyadjacent the quiescent position of the paddle vane. The connection cancomprise a slot defined in the wall of the chamber, the slot havingsimilar dimensions to a cross-sectional profile of the paddle vane. Thecentral arm can comprise substantially glass.

The apparatus is ideally suited for use in the form of ink jet printer.Each fluid ejection aperture preferably includes a rim defined around anouter surface thereof.

Preferably, a multiplicity of apparatuses can be arranged such that thefluid ejection apertures are grouped together spatially into spacedapart rows and fluid is ejected from the fluid ejection apertures ofeach of the rows in phases. The nozzle chambers can be further groupedinto multiple ink colors and with each of the nozzles being suppliedwith a corresponding ink color.

In accordance with a second aspect of the present invention, there isprovided a method of ejecting drops of fluid from a nozzle chamberhaving at least two nozzle apertures defined in the wall of the nozzlechambers utilizing a moveable paddle vane attached to an actuatormechanism, the method comprising the steps of actuating the actuator tocause the moveable paddle to move in a first direction so as to ejectdrops from a first of the nozzle apertures; and actuating the actuatorcausing the moveable paddle to move in a second direction so as to ejectdrops from a second of the nozzle apertures.

BRIEF DESCRIPTION OF THE DRAWINGS

Notwithstanding any other forms which may fall within the scope of thepresent invention, preferred forms of the invention will now bedescribed, by way of example only, with reference to the accompanyingdrawings in which:

FIGS. 1-5 comprise schematic illustrations of the operation of thepreferred embodiment;

FIG. 6 illustrates a side perspective view, of a single nozzlearrangement of the preferred embodiment.

FIG. 7 illustrates a perspective view, partly in section of a singlenozzle arrangement of the preferred embodiment;

FIGS. 8-27 are cross sectional views of the processing steps in theconstruction of the preferred embodiment;

FIG. 28 illustrates a part of an array view of a portion of a printheadas constructed in accordance with the principles of the presentinvention;

FIG. 29 provides a legend of the materials indicated in FIG. 30 to 42;and

FIG. 30 to FIG. 44 illustrate sectional views of the manufacturing stepsin one form of construction of an ink jet printhead nozzle.

DESCRIPTION OF PREFERRED AND OTHER EMBODIMENTS

In the preferred embodiment, there is provided an inkjet printheadhaving an array of nozzles wherein the nozzles are grouped in pairs andeach pair is provided with a single actuator which is actuated so as tomove a paddle type mechanism to force the ejection of ink out of one orother of the nozzle pairs. The paired nozzles eject ink from a singlenozzle chamber which is resupplied by means of an ink supply channel.Further, the actuator of the preferred embodiment has uniquecharacteristics so as to simplify the actuation process.

Turning initially to FIGS. 1 to 5, there will now be explained theprinciples of operation of the preferred embodiment. In the preferredembodiment, a single nozzle chamber 1 is utilized to supply ink two inkejection nozzles 2, 3. Ink is resupplied to the nozzle chamber 1 viameans of an ink supply channel 5. In its quiescent position, to inkmenisci 6, 7 are formed around the ink ejection holes 2, 3. Thearrangement of FIG. 1 being substantially axially symmetric around acentral paddle 9 which is attached to an actuator mechanism.

When it is desired to eject ink out of one of the nozzles, say nozzle 3,the paddle 9 is actuated so that it begins to move as indicated in FIG.2. The movement of paddle 9 in the direction 10 results in a generalcompression of the ink on the right hand side of the paddle 9. Thecompression of the ink results in the meniscus 7 growing as the ink isforced out of the nozzles 3. Further, the meniscus 6 undergoes aninversion as the ink is sucked back on the left hand side of theactuator 10 with additional ink 12 being sucked in from ink supplychannel 5. The paddle actuator 9 eventually comes to rest and begins toreturn as illustrated in FIG. 3. The ink 13 within meniscus 7 hassubstantial forward momentum and continues away from the nozzle chamberwhile the paddle 9 causes ink to be sucked back into the nozzle chamber.Further, the surface tension on the meniscus 6 results in further inflow of the ink via the ink supply channel 5. The resolution of theforces at work in the resultant flows results in a general necking andsubsequent breaking of the meniscus 7 as illustrated in FIG. 4 wherein adrop 14 is formed which continues onto the media or the like. The paddle9 continues to return to its quiescent position.

Next, as illustrated in FIG. 5, the paddle 9 returns to its quiescentposition and the nozzle chamber refills by means of surface tensioneffects acting on meniscuses 6, 7 with the arrangement of returning tothat showing in FIG. 1. When required, the actuator 9 can be activatedto eject ink out of the nozzle 2 in a symmetrical manner to thatdescribed with reference to FIG. 1-5. Hence, a single actuator 9 isactivated to provide for ejection out of multiple nozzles. The dualnozzle arrangement has a number of advantages including in that movementof actuator 9 does not result in a significant vacuum forming on theback surface of the actuator 9 as a result of its rapid movement.Rather, meniscus 6 acts to ease the vacuum and further acts as a “pump”for the pumping of ink into the nozzle chamber. Further, the nozzlechamber is provided with a lip 15 (FIG. 2) which assists in equalizingthe increase in pressure around the ink ejection holes 3 which allowsfor the meniscus 7 to grow in an actually symmetric manner therebyallowing for straight break off of the drop 14.

Turning now to FIGS. 6 and 7, there is illustrated a suitable nozzlearrangement with FIG. 6 showing a single side perspective view and FIG.7 showing a view, partly in section illustrating the nozzle chamber. Theactuator 20 includes a pivot arm attached at the post 21. The pivot armincludes an internal core portion 22 which can be constructed fromglass. On each side 23, 24 of the internal portion 22 is two separatelycontrol heater arms which can be constructed from an alloy of copper andnickel (45% copper and 55% nickel). The utilization of the glass core isadvantageous in that it has a low coefficient thermal expansion andcoefficient of thermal conductivity. Hence, any energy utilized in theheaters 23, 24 is substantially maintained in the heater structure andutilized to expand the heater structure and opposed to an expansion ofthe glass core 22. Structure or material chosen to form part of theheater structure preferably has a high “bend efficiency”. One form ofdefinition of bend efficiency can be the youngs modulus times thecoefficient of thermal expansion divided by the density and by thespecific heat capacity.

The copper nickel alloy in addition to being conductive has a highcoefficient of thermal expansion, a low specific heat and density inaddition to a high young's modulus. It is therefore a highly suitablematerial for construction of the heater element although other materialswould also be suitable.

Each of the heater elements can comprise a conductive out and returntrace with the traces being insulated from one and other along thelength of the trace and conductively joined together at the far end ofthe trace. The current supply for the heater can come from a lowerelectrical layer via the pivot anchor 21. At one end of the actuator 20,there is provided a bifurcated portion 30 which has attached at one endthereof to leaf portions 31, 32.

To operate the actuator, one of the arms 23, 24 eg. 23 is heated in airby passing current through it. The heating of the arm results in ageneral expansion of the arm. The expansion of the arm results in ageneral bending of the arm 20. The bending of the arm 20 further resultsin leaf portion 32 pulling on the paddle portion 9. The paddle 9 ispivoted around a fulcrum point by means of attachment to leaf portions38, 39 which are generally thin to allow for minor flexing. The pivotingof the arm 9 causes ejection of ink from the nozzle hole 40. The heateris deactivated resulting in a return of the actuator 20 to its quiescentposition and its corresponding return of the paddle 9 also to isquiescent position. Subsequently, to eject ink out of the other nozzlehole 41, the heater 24 can be activated with the paddle operating in asubstantially symmetric manner.

It can therefore be seen that the actuator can be utilized to move thepaddle 9 on demand so as to eject drops out of the ink ejection hole eg.40 with the ink refilling via an ink supply channel 44 located under thepaddle 9.

The nozzle arrangement of the preferred embodiment can be formed on asilicon wafer utilizing standard semi-conductor fabrication processingsteps and micro-electromechanical systems (MEMS) constructiontechniques.

For a general introduction to a micro-electro mechanical system (MEMS)reference is made to standard proceedings in this field including theproceeding of the SPIE (International Society for Optical Engineering)including volumes 2642 and 2882 which contain the proceedings of recentadvances and conferences in this field.

Preferably, a large wafer of printheads is constructed at any one timewith each printhead providing a predetermined pagewidth capabilities anda single printhead can in turn comprise multiple colors so as to providefor full color output as would be readily apparent to those skilled inthe art.

Turning now to FIG. 8-FIG. 27 there will now be explained one form offabrication of the preferred embodiment. The preferred embodiment canstart as illustrated in FIG. 8 with a CMOS processed silicon wafer 50which can include a standard CMOS layer 51 including of the relevantelectrical circuitry etc. The processing steps can then be as follows:

1. As illustrated in FIG. 9, a deep etch of the nozzle chamber 51 isperformed to a depth of 25 micron;

2. As illustrated in FIG. 10, a 27 micron layer of sacrificial material52 such as aluminum is deposited;

3. As illustrated in FIG. 11, the sacrificial material is etched to adepth of 26 micron using a glass stop so as to form cavities using apaddle and nozzle mask.

4. As illustrated in FIG. 12, a 2 micron layer of low stress glass 53 isdeposited.

5. As illustrated in FIG. 13, the glass is etched to the aluminum layerutilizing a first heater via mask.

6. As illustrated in FIG. 14, a 2 micron layer of 60% copper and 40%nickel is deposited 55 and planarized (FIG. 15) using chemicalmechanical planarization (CMP).

7. As illustrated in FIG. 16, a 0.1 micron layer of silicon nitride isdeposited 56 and etched using a heater insulation mask.

8. As illustrated in FIG. 17, a 2 micron layer of low stress glass 57 isdeposited and etched using a second heater mask.

9. As illustrated in FIG. 18, a 2 micron layer of 60% copper and 40%nickel is deposited 55 and planarized (FIG. 19) using chemicalmechanical planarization.

10. As illustrated in FIG. 20, a 1 micron layer of low stress glass 60is deposited and etched (FIG. 21) using a nozzle wall mask.

11. As illustrated in FIG. 22, the glass is etched down to thesacrificial layer using an actuator paddle wall mask.

12. As illustrated in FIG. 23, a 5 micron layer of sacrificial material62 is deposited and planarized using CMP.

13. As illustrated in FIG. 24, a 3 micron layer of low stress glass 63is deposited and etched using a nozzle rim mask.

14. As illustrated in FIG. 25, the glass is etched down to thesacrificial layer using nozzle mask.

15. As illustrated in FIG. 26, the wafer can be etched from the backusing a deep silicon trench etcher such as the Silicon TechnologySystems deep trench etcher.

16. Finally, as illustrated in FIG. 27, the sacrificial layers areetched away releasing the ink jet structure.

Subsequently, the print head can be washed, mounted on an ink chamber,relevant electrical interconnections TAB bonded and the print headtested.

Turning now to FIG. 28, there is illustrated a portion 80 of a fullcolour printhead which is divided into three series of nozzles 71, 72and 73. Each series can supply a separate color via means of acorresponding ink supply channel. Each series is further subdivided intotwo subrows e.g. 76, 77 with the relevant nozzles of each subrow beingfired simultaneously with one subrow being fired a predetermined timeafter a second subrow such that a line of ink drops is formed on a page.

As illustrated in FIG. 28 the actuators a formed in a curvedrelationship with respect to the main nozzle access so as to provide fora more compact packing of the nozzles. Further, the block portion (21 ofFIG. 6) is formed in the wall of an adjacent series with the blockportion of the row 73 being formed in a separate guide rail 80 providedas an abutment surface for the TAB strip when it is abutted against theguide rail 80 so as to provide for an accurate registration of the tabstrip with respect to the bond pads 81, 82 which are provided along thelength of the printhead so as to provide for low impedance driving ofthe actuators.

The principles of the preferred embodiment can obviously be readilyextended to other structures. For example, a fulcrum arrangement couldbe constructed which includes two arms which are pivoted around athinned wall by means of their attachment to a cross bar. Each arm couldbe attached to the central cross bar by means of similarly leafedportions to that shown in FIG. 6 and FIG. 7. The distance between afirst arm and the thinned wall can be L units whereas the distancebetween the second arm and wall can be NL units. Hence, when atranslational movement is applied to the second arm for a distance ofN×X units the first arm undergoes a corresponding movement of X units.The leafed portions allow for flexible movement of the arms whilestproviding for full pulling strength when required.

It would be evident to those skilled in the art that the presentinvention can further be utilized in either mechanical arrangementsrequiring the application forces to enduce movement in a structure.

One form of detailed manufacturing process which can be used tofabricate monolithic ink jet print heads operating in accordance withthe principles taught by the present embodiment can proceed utilizingthe following steps:

1. Using a double sided polished wafer, complete drive transistors, datadistribution, and timing circuits using a 0.5 micron, one poly, 2 metalCMOS process. Relevant features of the wafer at this step are shown inFIG. 30. For clarity, these diagrams may not be to scale, and may notrepresent a cross section though any single plane of the nozzle. FIG. 29is a key to representations of various materials in these manufacturingdiagrams, and those of other cross referenced ink jet configurations.

2. Etch oxide down to silicon or aluminum using Mask 1. This maskdefines the ink inlet, the heater contact vias, and the edges of theprint head chips. This step is shown in FIG. 31.

3. Etch exposed silicon to a depth of 20 microns. This step is shown inFIG. 32.

4. Deposit a 1 micron conformal layer of a first sacrificial material.

5. Deposit 20 microns of a second sacrificial material, and planarizedown to the first sacrificial layer using CMP. This step is shown inFIG. 33.

6. Etch the first sacrificial layer using Mask 2, defining the nozzlechamber wall, the paddle, and the actuator anchor point. This step isshown in FIG. 34.

7. Etch the second sacrificial layer down to the first sacrificial layerusing Mask 3. This mask defines the paddle. This step is shown in FIG.35.

8. Deposit a 1 micron conformal layer of PECVD glass.

9. Etch the glass using Mask 4, which defines the lower layer of theactuator loop.

10. Deposit 1 micron of heater material, for example titanium nitride(TiN) or titanium diboride (TiB2). Planarize using CMP. This step isshown in FIG. 36.

11. Deposit 0.1 micron of silicon nitride.

12. Deposit 1 micron of PECVD glass.

13. Etch the glass using Mask 5, which defines the upper layer of theactuator loop.

14. Etch the silicon nitride using Mask 6, which defines the viasconnecting the upper layer of the actuator loop to the lower layer ofthe actuator loop.

15. Deposit 1 micron of the same heater material previously deposited.Planarize using CMP. This step is shown in FIG. 37.

16. Deposit 1 micron of PECVD glass.

17. Etch the glass down to the sacrificial layer using Mask 6. This maskdefines the actuator and the nozzle chamber wall, with the exception ofthe nozzle chamber actuator slot. This step is shown in FIG. 38.

18. Wafer probe. All electrical connections are complete at this point,bond pads are accessible, and the chips are not yet separated.

19. Deposit 4 microns of sacrificial material and planarize down toglass using CMP.

20. Deposit 3 microns of PECVD glass. This step is shown in FIG. 39.

21. Etch to a depth of (approx.) 1 micron using Mask 7. This maskdefines the nozzle rim. This step is shown in FIG. 40.

22. Etch down to the sacrificial layer using Mask 8. This mask definesthe roof of the nozzle chamber, and the nozzle itself. This step isshown in FIG. 41.

23. Back-etch completely through the silicon wafer (with, for example,an ASE Advanced Silicon Etcher from Surface Technology Systems) usingMask 9. This mask defines the ink inlets which are etched through thewafer. The wafer is also diced by this etch. This step is shown in FIG.42.

24. Etch both types of sacrificial material. The nozzle chambers arecleared, the actuators freed, and the chips are separated by this etch.This step is shown in FIG. 43.

25. Mount the print heads in their packaging, which may be a moldedplastic former incorporating ink channels which supply the appropriatecolor ink to the ink inlets at the back of the wafer.

26. Connect the print heads to their interconnect systems. For a lowprofile connection with minimum disruption of airflow, TAB may be used.Wire bonding may also be used if the printer is to be operated withsufficient clearance to the paper.

27. Hydrophobize the front surface of the print heads.

28. Fill the completed print heads with ink and test them. A fillednozzle is shown in FIG. 44.

The presently disclosed ink jet printing technology is potentiallysuited to a wide range of printing system including: colour andmonochrome office printers, short run digital printers, high speeddigital printers, offset press supplemental printers, low cost scanningprinters high speed pagewidth printers, notebook computers with inbuiltpagewidth printers, portable colour and monochrome printers, colour andmonochrome copiers, colour and monochrome facsimile machines, combinedprinter, facsimile and copying machines, label printers, large formatplotters, photograph copiers, printers for digital photographic“minilabs”, video printers, PhotoCD printers, portable printers forPDAs, wallpaper printers, indoor sign printers, billboard printers,fabric printers, camera printers and fault tolerant commercial printerarrays.

It would be appreciated by a person skilled in the art that numerousvariations and/or modifications may be made to the present invention asshown in the specific embodiments without departing from the spirit orscope of the invention as broadly described. The present embodimentsare, therefore, to be considered in all respects to be illustrative andnot restrictive.

Ink Jet Technologies

The embodiments of the invention use an ink jet printer type device. Ofcourse many different devices could be used. However presently popularink jet printing technologies are unlikely to be suitable.

The most significant problem with thermal inkjet is power consumption.This is approximately 100 times that required for high speed, and stemsfrom the energy-inefficient means of drop ejection. This involves therapid boiling of water to produce a vapor bubble which expels the ink.Water has a very high heat capacity, and must be superheated in thermalinkjet applications. This leads to an efficiency of around 0.02%, fromelectricity input to drop momentum (and increased surface area) out.

The most significant problem with piezoelectric inkjet is size and cost.Piezoelectric crystals have a very small deflection at reasonable drivevoltages, and therefore require a large area for each nozzle. Also, eachpiezoelectric actuator must be connected to its drive circuit on aseparate substrate. This is not a significant problem at the currentlimit of around 300 nozzles per print head, but is a major impediment tothe fabrication of pagewide print heads with 19,200 nozzles.

Ideally, the inkjet technologies used meet the stringent requirements ofin-camera digital color printing and other high quality, high speed, lowcost printing applications. To meet the requirements of digitalphotography, new inkjet technologies have been created. The targetfeatures include:

low power (less than 10 Watts)

high resolution capability (1,600 dpi or more)

photographic quality output

low manufacturing cost

small size (pagewidth times minimum cross section)

high speed (<2 seconds per page).

All of these features can be met or exceeded by the inkjet systemsdescribed below with differing levels of difficulty. 45 different inkjettechnologies have been developed by the Assignee to give a wide range ofchoices for high volume manufacture. These technologies form part ofseparate applications assigned to the present Assignee as set out in thetable below.

The inkjet designs shown here are suitable for a wide range of digitalprinting systems, from battery powered one-time use digital cameras,through to desktop and network printers, and through to commercialprinting systems

For ease of manufacture using standard process equipment, the print headis designed to be a monolithic 0.5 micron CMOS chip with MEMS postprocessing. For color photographic applications, the print head is 100mm long, with a width which depends upon the inkjet type. The smallestprint head designed is IJ38, which is 0.35 mm wide, giving a chip areaof 35 square mm. The print heads each contain 19,200 nozzles plus dataand control circuitry.

Ink is supplied to the back of the print head by injection moldedplastic ink channels. The molding requires 50 micron features, which canbe created using a lithographically micromachined insert in a standardinjection molding tool. Ink flows through holes etched through the waferto the nozzle chambers fabricated on the front surface of the wafer. Theprint head is connected to the camera circuitry by tape automatedbonding.

CROSS-REFERENCED APPLICATIONS

The following table is a guide to cross-referenced patent applicationsfiled concurrently herewith and discussed hereinafter with the referencebeing utilized in subsequent tables when referring to a particular case:

Docket No. Reference Title IJ01US IJ01 Radiant Plunger Ink Jet PrinterIJ02US IJ02 Electrostatic Ink Jet Printer IJ03US IJ03 PlanarThermoelastic Bend Actuator Ink Jet IJ04US IJ04 Stacked ElectrostaticInk Jet Printer IJ05US IJ05 Reverse Spring Lever Ink Jet Printer IJ06USIJ06 Paddle Type Ink Jet Printer IJ07US IJ07 Permanent MagnetElectromagnetic Ink Jet Printer IJ08US IJ08 Planar Swing GrillElectromagnetic Ink Jet Printer IJ09US IJ09 Pump Action Refill Ink JetPrinter IJ10US IJ10 Pulsed Magnetic Field Ink Jet Printer IJ11US IJ11Two Plate Reverse Firing Electromagnetic Ink Jet Printer IJ12US IJ12Linear Stepper Actuator Ink Jet Printer IJ13US IJ13 Gear Driven ShutterInk Jet Printer IJ14US IJ14 Tapered Magnetic Pole Electromagnetic InkJet Printer IJ15US IJ15 Linear Spring Electromagnetic Grill Ink JetPrinter IJ16US IJ16 Lorenz Diaphragm Electromagnetic Ink Jet PrinterIJ17US IJ17 PTFE Surface Shooting Shuttered Oscillating Pressure Ink JetPrinter IJ18US IJ18 Buckle Grip Oscillating Pressure Ink Jet PrinterIJ19US IJ19 Shutter Based Ink Jet Printer IJ20US IJ20 Curling CalyxThermoelastic Ink Jet Printer IJ21US IJ21 Thermal Actuated Ink JetPrinter IJ22US IJ22 Iris Motion Ink Jet Printer IJ23US IJ23 DirectFiring Thermal Bend Actuator Ink Jet Printer IJ24US IJ24 Conductive PTFEBen Activator Vented Ink Jet Printer IJ25US IJ25 Magnetostrictive InkJet Printer IJ26US IJ26 Shape Memory Alloy Ink Jet Printer IJ27US IJ27Buckle Plate Ink Jet Printer IJ28US IJ28 Thermal Elastic Rotary ImpellerInk Jet Printer IJ29US IJ29 Thermoelastic Bend Actuator Ink Jet PrinterIJ30US IJ30 Thermoelastic Bend Actuator Using PTFE and Corrugated CopperInk Jet Printer IJ31US IJ31 Bend Actuator Direct Ink Supply Ink JetPrinter IJ32US IJ32 A High Young's Modulus Thermoelastic Ink Jet PrinterIJ33US IJ33 Thermally actuated slotted chamber wall ink Jet printerIJ34US IJ34 Ink Jet Printer having a thermal actuator comprising anexternal coiled spring IJ35US IJ35 Trough Container Ink Jet PrinterIJ36US IJ36 Dual Chamber Single Vertical Actuator Ink Jet IJ37US IJ37Dual Nozzle Single Horizontal Fulcrum Actuator Ink Jet IJ38US IJ38 DualNozzle Single Horizontal Actuator Ink Jet IJ39US IJ39 A single bendactuator cupped paddle ink jet printing device IJ40US IJ40 A thermallyactuated ink jet printer having a series of thermal actuator unitsIJ41US IJ41 A thermally actuated ink jet printer including a taperedheater element IJ42US IJ42 Radial Back-Curling Thermoelastic Ink JetIJ43US IJ43 Inverted Radial Back-Curling Thermoelastic Ink Jet IJ44USIJ44 Surface bend actuator vented ink supply ink jet printer IJ45US IJ45Coil Actuated Magnetic Plate Ink Jet Printer

Tables of Drop-on-Demand Inkjets

Eleven important characteristics of the fundamental operation ofindividual inkjet nozzles have been identified. These characteristicsare largely orthogonal, and so can be elucidated as an elevendimensional matrix. Most of the eleven axes of this matrix includeentries developed by the present assignee.

The following tables form the axes of an eleven dimensional table ofinkjet types.

Actuator mechanism (18 types)

Basic operation mode (7 types)

Auxiliary mechanism (8 types)

Actuator amplification or modification method (17 types)

Actuator motion (19 types)

Nozzle refill method (4 types)

Method of restricting back-flow through inlet (10 types)

Nozzle clearing method (9 types)

Nozzle plate construction (9 types)

Drop ejection direction (5 types)

Ink type (7 types)

The complete eleven dimensional table represented by these axes contains36.9 billion possible configurations of inkjet nozzle. While not all ofthe possible combinations result in a viable inkjet technology, manymillion configurations are viable. It is clearly impractical toelucidate all of the possible configurations. Instead, certain inkjettypes have been investigated in detail. These are designated IJ01 toIJ45 above.

Other inkjet configurations can readily be derived from these 45examples by substituting alternative configurations along one or more ofthe 11 axes. Most of the IJ01 to IJ45 examples can be made into inkjetprint heads with characteristics superior to any currently availableinkjet technology.

Where there are prior art examples known to the inventor, one or more ofthese examples are listed in the examples column of the tables below.The IJ01 to IJ45 series are also listed in the examples column. In somecases, a printer may be listed more than once in a table, where itshares characteristics with more than one entry.

Suitable applications include: Home printers, Office network printers,Short run digital printers, Commercial print systems, Fabric printers,Pocket printers, Internet WWW printers, Video printers, Medical imaging,Wide format printers, Notebook PC printers, Fax machines, Industrialprinting systems, Photocopiers, Photographic minilabs etc.

The information associated with the aforementioned 11 dimensional matrixare set out in the following tables.

ACTUATOR MECHANISM (APPLIED ONLY TO SELECTED INK DROPS) ActuatorMechanism Description Advantages Disadvantages Examples Thermal Anelectrothermal heater heats the ♦ Large force generated ♦ High power ♦Canon Bubblejet bubble ink to above boiling point, ♦ Simple construction♦ Ink carrier limited to water   1979 Endo et al GB transferringsignificant heat to the ♦ No moving parts ♦ Low efficiency   patent2,007,162 aqueous ink. A bubble nucleates and ♦ Fast operation ♦ Hightemperatures required ♦ Xerox heater-in-pit quickly forms, expelling theink. ♦ Small chip area required for ♦ High mechanical stress   1990Hawkins et al The efficiency of the process is low,   actuator ♦ Unusualmaterials required   U.S. Pat. No. 4,899,181 with typically less than0.05% of the ♦ Large drive transistors ♦ Hewlett-Packard TIJ electricalenergy being transformed ♦ Cavitation causes actuator failure   1982Vaught et al into kinetic energy of the drop. ♦ Kogation reduces bubbleformation   U.S. Pat. No. 4,490,728 ♦ Large print heads are difficult to  fabricate Piezoelectric A piezoelectric crystal such as lead ♦ Lowpower consumption ♦ Very large area required for actuator ♦ Kyser et allanthanum zirconate (PZT) is ♦ Many ink types can be used ♦ Difficult tointegrate with electronics   U.S. Pat. No. 3,946,398 electricallyactivated, and either ♦ Fast operation ♦ High voltage drive transistorsrequired ♦ Zoltan expands, shears, or bends to apply ♦ High efficiency ♦Full pagewidth print heads impractical   U.S. Pat. No. 3,683,212pressure to the ink, ejecting drops.   due to actuator size ♦ 1973Stemme ♦ Requires electrical poling in high field   U.S. Pat. No.3,747,120   strengths during manufacture ♦ Epson Stylus ♦ Tektronix ♦IJ04 Electro- An electric field is used to activate ♦ Low powerconsumption ♦ Low maximum strain (approx. 0.01%) ♦ Seiko Epson, Usui etstrictive electrostriction in relaxor materials ♦ Many ink types can beused ♦ Large area required for actuator due to   all JP 253401/96 suchas lead lanthanum zirconate ♦ Low thermal expansion   low strain ♦ IJ04titanate (PLZT) or lead magnesium ♦ Electric field strength ♦ Responsespeed is marginal (˜10 μs) niobate (PMN).   required (approx. 3.5 V/μm)♦ High voltage drive transistors required   can be generated without ♦Full pagewidth print heads impractical   difficulty   due to actuatorsize ♦ Does not require electrical   poling Ferroelectric An electricfield is used to induce a ♦ Low power consumption ♦ Difficult tointegrate with electronics ♦ IJ04 phase transition between the ♦ Manyink types can be used ♦ Unusual materials such as PLZSnT areantiferroelectric (AFE) and ♦ Fast operation (<1 μs)   requiredferroelectric (FE) phase. Perovskite ♦ Relatively high longitudinal ♦Actuators require a large area materials such as tin modified lead  strain lanthanum zirconate titanate ♦ High efficiency (PLZSnT) exhibitlarge strains of up ♦ Electric field strength of to 1% associated withthe AFE to FE   around 3 V/μm can be phase transition.   readilyprovided Electrostatic Conductive plates are separated by a ♦ Low powerconsumption ♦ Difficult to operate electostatic ♦ IJ02, IJ04 platescompressible or fluid dielectric ♦ Many ink types can be used   devicesin an aqueous environment (usually air). Upon application of a ♦ Fastoperation ♦ The electrostatic actuator will normally voltage, the platesattract each other   need to be separated from the ink and displace ink,causing drop ♦ Very large area required to achieve ejection. Theconductive plates may   high forces be in a comb or honeycomb ♦ Highvoltage drive transistors may be structure, or stacked to increase the  required surface area and therefore the force. ♦ Full pagewidth printheads are not   competitive due to actuator size Electrostatic A strongelectric field is applied to ♦ Low current consumption ♦ High voltagerequired ♦ 1989 Saito et al, pull on ink the ink, whereuponelectrostatic ♦ Low temperature ♦ May be damaged by sparks due to air  U.S. Pat. No. 4,799,068 attraction accelerates the ink towards  breakdown ♦ 1989 Miura et al, the print medium. ♦ Required fieldstrength increases as the   U.S. Pat. No. 4,810,954   drop sizedecreases ♦ Tone-jet ♦ High voltage drive transistors required ♦Electrostatic field attracts dust Permanent An electromagnet directlyattracts a ♦ Low power consumption ♦ Complex fabrication ♦ IJ07, IJ10magnet permanent magnet, displacing ink ♦ Many ink types can be used ♦Permanent magnetic material such as electro- and causing drop ejection.Rare earth ♦ Fast operation   Neodymium Iron Boron (NdFeB) magneticmagnets with a field strength around ♦ High efficiency   required. 1Tesla can be used. Examples are: ♦ Easy extension from single ♦ Highlocal currents required Samarium Cobalt (SaCo) and   nozzles topagewidth print ♦ Copper metalization should be used for magneticmaterials in the   heads   long electromigration lifetime and lowneodymium iron boron family   resistivity (NdFeB, NdDyFeBNb, NdDyFeB, ♦Pigmented inks are usually infeasible etc) ♦ Operating temperaturelimited to the   Curie temperature (around 540 K.) Soft magnetic Asolenoid induced a magnetic field ♦ Low power consumption ♦ Complexfabrication ♦ IJ01, IJ05, IJ08, IJ10 core electro- in a soft magneticcore or yoke ♦ Many ink types can be used ♦ Materials not usuallypresent in a ♦ IJ12, IJ14, IJ15, IJ17 magnetic fabricated from a ferrousmaterial ♦ Fast operation   CMOS fab such as NiFe, CoNiFe, or such aselectroplated iron alloys such ♦ High efficiency   CoFe are required asCoNiFe [1], CoFe, or NiFe alloys. ♦ Easy extension from single ♦ Highlocal currents required Typically, the soft magnetic material   nozzlesto pagewidth print ♦ Copper metalization should be used for is in twoparts, which are normally   heads   long electromigration lifetime andlow held apart by a spring. When the   resistivity solenoid is actuated,the two parts ♦ Electroplating is required attract, displacing the ink.♦ High saturation flux density is required   (2.0-2.1 T is achievablewith CoNiFe   [1]) Magnetic The Lorenz force acting on a current ♦ Lowpower consumption ♦ Force acts as a twisting motion ♦ IJ06, IJ11, IJ13,IJ16 Lorenz force carrying wire in a magnetic field is ♦ Many ink typescan be used ♦ Typically, only a quarter of the utilized. ♦ Fastoperation   solenoid length provides force in a This allows the magneticfield to be ♦ High efficiency   useful direction supplied externally tothe print head, ♦ Easy extension from single ♦ High local currentsrequired for example with rare earth   nozzles to pagewidth print ♦Copper metalization should be used for permanent magnets.   heads   longelectromigration lifetime and low Only the current carrying wire need  resistivity be fabricated on the print-head, ♦ Pigmented inks areusually infeasible simplifying materials requirements. Magneto- Theactuator uses the giant ♦ Many ink types can be used ♦ Force acts as atwisting motion ♦ Fischenbeck, striction magnetostrictive effect ofmaterials ♦ Fast operation ♦ Unusual materials such as Terfenol-D   U.S.Pat. No. 4,032,929 such as Terfenol-D (an alloy of ♦ Easy extension fromsingle   are required ♦ IJ25 terbium, dysprosium and iron   nozzles topagewidth print ♦ High local currents required developed at the NavalOrdnance   heads ♦ Copper metalization should be used for Laboratory,hence Ter-Fe-NOL). For ♦ High force is available   long electromigrationlifetime and low best efficiency, the actuator should   resistivity bepre-stressed to approx. 8 MPa. ♦ Pre-stressing may be required SurfaceInk under positive pressure is held in ♦ Low power consumption ♦Requires supplementary force to effect ♦ Silverbrook, EP 0771 tension anozzle by surface tension. The ♦ Simple construction   drop separation  658 A2 and related reduction surface tension of the ink is reduced ♦ Nounusual materials ♦ Requires special ink surfactants   patentapplications below the bubble threshold, causing   required infabrication ♦ Speed may be limited by surfactant the ink to egress fromthe nozzle. ♦ High efficiency   properties ♦ Easy extension from single  nozzles to pagewidth print   heads Viscosity The ink viscosity islocally reduced ♦ Simple construction ♦ Requires supplementary force toeffect ♦ Silverbrook, EP 0771 reduction to select which drops are to be♦ No unusual materials   drop separation   658 A2 and related ejected. Aviscosity reduction can be   required in fabrication ♦ Requires specialink viscosity   patent applications achieved electrothermally with most♦ Easy extension from single   properties inks, but special inks can be  nozzles to pagewidth print ♦ High speed is difficult to achieveengineered for a 100:1 viscosity   heads ♦ Requires oscillating inkpressure reduction. ♦ A high temperature difference   (typically 80degrees) is required Acoustic An acoustic wave is generated and ♦ Canoperate without a ♦ Complex drive circuitry ♦ 1993 Hadimioglu etfocussed upon the drop ejection   nozzle plate ♦ Complex fabrication  al, EUP 550,192 region. ♦ Low efficiency ♦ 1993 Elrod et al, EUP ♦ Poorcontrol of drop position   572,220 ♦ Poor control of drop volumeThermoelastic An actuator which relies upon ♦ Low power consumption ♦Efficient aqueous operation requires a ♦ IJ03, IJ09, IJ17, IJ18 bendactuator differential thermal expansion upon ♦ Many ink types can beused   thermal insulator on the hot side ♦ IJ19, IJ20, IJ21, IJ22 Jouleheating is used. ♦ Simple planar fabrication ♦ Corrosion prevention canbe difficult ♦ IJ23, IJ24, IJ27, IJ28 ♦ Small chip area required for ♦Pigmented inks may be infeasible, as ♦ IJ29, IJ30, IJ31, IJ32   eachactuator   pigment particles may jam the bend ♦ IJ33, IJ34, IJ35, IJ36 ♦Fast operation   actuator ♦ IJ37, IJ38, IJ39, IJ40 ♦ High efficiency ♦IJ41 ♦ CMOS compatible voltages   and currents ♦ Standard MEMS processes  can be used ♦ Easy extension from single   nozzles to pagewidth print  heads High CTE A material with a very high ♦ High force can begenerated ♦ Requires special material (e.g. PTFE) ♦ IJ09, IJ17, IJ18,IJ20 thermoelastic coefficient of thermal expansion ♦ PTFE is acandidate for low ♦ Requires a PTFE deposition process, ♦ IJ21, IJ22,IJ23, IJ24 actuator (CTE) such as   dielectric constant   which is notyet standard in ULSI fabs ♦ IJ27, IJ28, IJ29, IJ30polytetrafluoroethylene (PTFE) is   insulation in ULSI ♦ PTFE depositioncannot be followed ♦ IJ31, IJ42, IJ43, IJ44 used. As high CTE materialsare ♦ Very low power   with high temperature (above 350° C.) usuallynon-conductive, a heater   consumption   processing fabricated from aconductive ♦ Many ink types can be used ♦ Pigmented inks may beinfeasible, as material is incorporated. A 50 μm ♦ Simple planarfabrication   pigment particles may jam the bend long PTFE bend actuatorwith ♦ Small chip area required for   actuator polysilicon heater and 15mW power   each actuator input can provide 180 μN force and ♦ Fastoperation 10 μm deflecton. Actuator motions ♦ High efficiency include: ♦CMOS compatible voltages 1) Bend   and currents 2) Push ♦ Easy extensionfrom single 3) Buckle   nozzles to pagewidth print 4) Rotate   headsConductive A polymer with a high coefficient of ♦ High force can begenerated ♦ Requires special materials ♦ IJ24 polymer thermal expansion(such as PTFE) is ♦ Very low power   development (High CTE conductivethermoelastic doped with conducting substances to   consumption  polymer) actuator increase its conductivity to about 3 ♦ Many ink typescan be used ♦ Requires a PTFE deposition process, orders of magnitudebelow that of ♦ Simple planar fabrication   which is not yet standard inULSI fabs copper. The conducting polymer ♦ Small chip area required for♦ PTFE deposition cannot be followed expands when resistively heated.  each actuator   with high temperature (above 350° C.) Examples ofconducting dopants ♦ Fast operation   processing include: ♦ Highefficiency ♦ Evaporation and CVD deposition 1) Carbon nanotubes ♦ CMOScompatible voltages   techniques cannot be used 2) Metal fibers   andcurrents ♦ Pigmented inks may be infeasible, as 3) Conductive polymerssuch as ♦ Easy extension from single   pigment particles may jam thebend   doped polythiophene   nozzles to pagewidth print   actuator 4)Carbon granules   heads Shape memory A shape memory alloy such as TiNi ♦High force is available ♦ Fatigue limits maximum number of ♦ IJ26 alloy(also known as Nitinol - Nickel   (stresses of hundred of   cyclesTitanium alloy developed at the   MPa) ♦ Low strain (1%) is required toextend Naval Ordnance Laboratory) is ♦ Large strain is available  fatigue resistance thermally switched between its weak   (more than 3%)♦ Cycle rate limited by heat removal martensitic state and its high ♦High corrosion resistance ♦ Requires unusual materials (TiNi) stiffnessaustenic state. The shape of ♦ Simple construction ♦ The latent heat oftransformation must the actuator in its martensitic state is ♦ Easyextension from single   be provided deformed relative to the austenic  nozzles to pagewidth print ♦ High current operation shape. The shapechange causes   heads ♦ Requires pre-stressing to distort the ejectionof a drop. ♦ Low voltage operation   martensitic state Linear Linearmagnetic actuators include ♦ Linear Magnetic actuators ♦ Requiresunusual semiconductor ♦ IJ12 Magnetic the Linear Induction Actuator(LIA),   can be constructed with   materials such as soft magneticalloys Actuator Linear Permanent Magnet   high thrust, long travel, and  (e.g. CoNiFe [1]) Synchronous Actuator (LPMSA),   high efficiencyusing planar ♦ Some varieties also require permanent Linear ReluctanceSynchronous   semiconductor fabrication   magnetic materials such asActuator (LRSA), Linear Switched   techniques   Neodymium iron boron(NdFeB) Reluctance Actuator (LSRA), and ♦ Long actuator travel is ♦Requires complex multi-phase drive the Linear Stepper Actuator (LSA).  available   circuitry ♦ Medium force is available ♦ High currentoperation ♦ Low voltage operation

BASIC OPERATION MODE Opera- tional mode Description AdvantagesDisadvantages Examples Actuator This is the simplest mode of ♦ Simpleoperation ♦ Drop repetition rate is usually limited ♦ Thermal inkjetdirectly operation: the actuator directly ♦ No external fields to lessthan 10 KHz. However, this is ♦ Piezoelectric inkjet pushes ink suppliessufficient kinetic energy to required not fundamental to the method, butis ♦ IJ01, IJ02, IJ03, IJ04 expel the drop. The drop must have a ♦Satellite drops can be related to the refill method normally ♦ IJ05,IJ06, IJ07, IJ09 sufficient velocity to overcome the avoided if dropused ♦ IJ11, IJ12, IJ14, IJ16 surface tension. velocity is less ♦ All ofthe drop kinetic energy ♦ IJ20, IJ22, IJ23, IJ24 than 4 m/s must beprovided by the actuator ♦ IJ25, IJ26, IJ27, IJ28 ♦ Can be efficient, ♦Satellite drops usually form if drop ♦ IJ29, IJ30, IJ31, IJ32 dependingupon the velocity is greater than 4.5 m/s ♦ IJ33, IJ34, IJ35, IJ36actuator used ♦ IJ37, IJ38, IJ39, IJ40 ♦ IJ41, IJ42, IJ43, IJ44Proximity The drops to be printed are selected ♦ Very simple print head♦ Requires close proximity between the ♦ Silverbrook, EP 0771 by somemanner (e.g. thermally fabrication can be used print head and the printmedia or 658 A2 and related induced surface tension reduction of ♦ Thedrop selection transfer roller patent applications pressurized ink).Selected drops are means does not need ♦ May require two print headsprinting separated from the ink in the nozzle to provide the energyalternate rows of the image by contact with the print medium or requiredto separate ♦ Monolithic color print heads are a transfer roller. thedrop from the difficult nozzle Electro- The drops to be printed areselected ♦ Very simple print head ♦ Requires very high electrostaticfield ♦ Silverbrook, EP 0771 static by some manner (e.g. thermallyfabrication can be used ♦ Electrostatic field for small nozzle 658 A2and related pull on induced surface tension reduction of ♦ The dropselection sizes is above air breakdown patent applications inkpressurized ink). Selected drops are means does not need ♦ Electrostaticfield may attract dust ♦ Tone-Jet separated from the ink in the nozzleto provide the energy by a strong electric field. required to separatethe drop from the nozzle. Magnetic The drops to be printed are selectedVery simple print ♦ Requires magnetic ink ♦ Silverbrook, EP 0771 pull onby some manner (e.g. thermally head fabrication ♦ Ink colors other thanblack are 658 A2 and related ink induced surface tension reduction ofcan be used difficult patent applications pressurized ink). Selecteddrops are ♦ The drop selection ♦ Requires very high magnetic fieldsseparated from the ink in the nozzle means does not need by a strongmagnetic field acting on to provide the energy the magnetic ink.required to separate the drop from the nozzle Shutter The actuator movesa shutter to ♦ High speed (>50 KHz) ♦ Moving parts are required ♦ IJ13,IJ17, IJ21 block ink flow to the nozzle. The ink operation can be ♦Requires ink pressure modulator pressure is pulsed at a multiple of theachieved due to ♦ Friction and wear must be considered drop ejectionfrequency. reduced refill time ♦ Striction is possible ♦ Drop timing canbe very accurate ♦ The actuator energy can be very low Shuttered Theactuator moves a shutter to ♦ Actuators with small ♦ Moving parts arerequired ♦ IJ08, IJ15, IJ18, IJ19 grill blocking flow through a grill tothe travel can be used ♦ Requires ink pressure modulator nozzle. Theshutter movement need ♦ Actuators with small ♦ Friction and wear must beconsidered only be equal to the width of the grill force can be used ♦Striction is possible holes. ♦ High speed (>50 KHz) operation can beachieved Pulsed A pulsed magnetic field attracts an ♦ Extremely lowenergy ♦ Requires an external pulsed magnetic ♦ IJ10 magnetic ‘inkpusher’ at the drop ejection operation is possible field pull onfrequency. An actuator controls a ♦ No heat dissipation ♦ Requiresspecial materials for ink pusher catch, which prevents the ink pusherproblems both the actuator and the ink pusher from moving when a drop isnot to ♦ Complex construction be ejected.

AUXILIARY MECHANISM (APPLIED TO ALL NOZZLES) Auxiliary MechanismDescription Advantages Disadvantages Examples None The actuator directlyfires the ink ♦ Simplicity of construction ♦ Drop ejection energy must ♦Most inkjets, drop, and there is no external field or ♦ Simplicity ofoperation be supplied by individual including other mechanism required.♦ Small physical size nozzle actuator piezoelectric and thermal bubble.♦ IJ01-IJ07, IJ09, IJ11 ♦ IJ12, IJ14, IJ20, IJ22 ♦ IJ23-IJ45 Oscillatingink The ink pressure oscillates, ♦ Oscillating ink pressure can ♦Requires external ink ♦ Silverbrook, EP 0771 pressure providing much ofthe drop ejection provide a refill pulse, pressure oscillator 658 A2 andrelated (including energy. The actuator selects which allowing higheroperating ♦ Ink pressure phase and patent applications acoustic dropsare to be fired by selectively speed amplitude must be carefully ♦ IJ08,IJ13, IJ15, IJ17 stimulation) blocking or enabling nozzles. The ♦ Theactuators may operate controlled ♦ IJ18, IJ19, IJ21 ink pressureoscillation may be with much lower energy ♦ Acoustic reflections in theachieved by vibrating the print head, ♦ Acoustic lenses can be used inkchamber must be or preferably by an actuator in the to focus the soundon the designed for ink supply. nozzles Media The print head is placedin close ♦ Low power ♦ Precision assembly required ♦ Silverbrook, EP0771 proximity proximity to the print medium. ♦ High accuracy ♦ Paperfibers may cause 658 A2 and related Selected drops protrude from the ♦Simple print head problems patent applications print head further thanunselected construction ♦ Cannot print on rough drops, and contact theprint medium. substrates The drop soaks into the medium fast enough tocause drop separation. Transfer roller Drops are printed to a transferroller ♦ High accuracy ♦ Bulky ♦ Silverbrook, EP 0771 instead ofstraight to the print ♦ Wide range of print ♦ Expensive 658 A2 andrelated medium. A transfer roller can also be substrates can be used ♦Complex construction patent applications used for proximity dropseparation. ♦ Ink can be dried on the ♦ Tektronix hot melt transferroller piezoelectric inkjet Electrostatic An electric field is used toaccelerate ♦ Low power ♦ Field strength required ♦ Any of the IJ seriesselected drops towards the print ♦ Simple print head for separation ofsmall ♦ Silverbrook, EP 0771 medium. construction drops is near or aboveair 658 A2 and related breakdown patent applications ♦ Tone-Jet Direct Amagnetic field is used to accelerate ♦ Low power ♦ Requires magnetic ink♦ Silverbrook, EP 0771 magnetic field selected drops of magnetic ink ♦Simple print head ♦ Requires strong magnetic 658 A2 and related towardsthe print medium. construction field patent applications Cross The printhead is placed in a constant ♦ Does not require magnetic ♦ Requiresexternal magnet ♦ IJ06, IJ16 magnetic field magnetic field. The Lorenzforce in a materials to be integrated in ♦ Current densities may becurrent carrying wire is used to move the print head high, resulting inelectro- the actuator. manufacturing process migration problems Pulsed Apulsed magnetic field is used to ♦ Very low power operation ♦ Complexprint head ♦ IJ10 magnetic field cyclically attract a paddle, which ispossible construction pushes on the ink. A small actuator ♦ Small printhead size ♦ Magnetic materials required moves a catch, which selectivelyin print head prevents the paddle from moving.

ACTUATOR AMPLIFICATION OR MODIFICATION METHOD Actuator amplifi- cationDescription Advantages Disadvantages Examples None No actuatormechanical ♦ Operational simplicity ♦ Many actuator mechanisms have ♦Thermal Bubble amplification is used. The actuator insufficient travel,or insufficient Inkjet directly drives the drop ejection force, toefficiently drive ♦ IJ01, IJ02, IJ06, IJ07 process. the drop ejectionprocess ♦ IJ16, IJ25, IJ26 Differ- An actuator material expands more ♦Provides greater travel ♦ High stresses are involved ♦ Piezoelectricential on one side than on the other. The in a reduced print head ♦ Caremust be taken that the materials ♦ IJ03, IJ09, IJ17-IJ24 expansionexpansion may be thermal, area do not delaminate ♦ IJ27, IJ29-IJ39,IJ42, bend piezoelectric, magnetostrictive, or ♦ The bend actuator ♦Residual bend resulting from high ♦ IJ43, IJ44 actuator other mechanism.converts a high force temperature or high stress during low travelactuator formation mechanism to high travel, lower force mechanismTransient A trilayer bend actuator where the ♦ Very good temperature ♦High stresses are involved ♦ IJ40, IJ41 bend two outside layers areidentical. This stability ♦ Care must be taken that the materialsactuator cancels bend due to ambient ♦ High speed, as a new do notdelaminate temperature and residual stress. The drop can be firedactuator only responds to transient before heat dissipates heating ofone side or the other. ♦ Cancels residual stress of formation Actuator Aseries of thin actuators are stacked. ♦ Increased travel ♦ Increasedfabrication complexity ♦ Some piezoelectric stack This can beappropriate where ♦ Reduced drive voltage ♦ Increased possibility ofshort circuits ink jets actuators require high electric field due topinholes ♦ IJ04 strength, such as electrostatic and piezoelectricactuators. Multiple Multiple smaller actuators are used ♦ Increases theforce ♦ Actuator forces may not add linearly, ♦ IJ12, IJ13, IJ18, IJ20actuators simultaneously to move the ink. available from an reducingefficiency ♦ IJ22, IJ28, IJ42, IJ43 Each actuator need provide only aactuator portion of the force required. ♦ Multiple actuators can bepositioned to control ink flow accurately Linear A linear spring is usedto transform a ♦ Matches low travel ♦ Requires print head area for the ♦IJ15 Spring motion with small travel and high actuator with higherspring force into a longer travel, lower force travel requirementsmotion. ♦ Non-contact method of motion transformation Reverse Theactuator loads a spring. When ♦ Better coupling to the ♦ Fabricationcomplexity ♦ IJ05, IJ11 spring the actuator is turned off, the springink ♦ High stress in the spring releases. This can reverse theforce/distance curve of the actuator to make it compatible with theforce/time requirements of the drop ejection. Coiled A bend actuator iscoiled to provide ♦ Increases travel ♦ Generally restricted to planar ♦IJ17, IJ21, IJ34, IJ35 actuator greater travel in a reduced chip area. ♦Reduces chip area implementations due to extreme ♦ Planar implementa-fabrication difficulty in other tions are relatively orientations. easyto fabricate. Flexure A bend actuator has a small region ♦ Simple meansof ♦ Care must be taken not to exceed the ♦ IJ10, IJ19, IJ33 bend nearthe fixture point, which flexes increasing travel of elastic limit inthe flexure area actuator much more readily than the a bend actuator ♦Stress distribution is very uneven remainder of the actuator. The ♦Difficult to accurately model with actuator flexing is effectivelyfinite element analysis converted from an even coiling to an angularbend, resulting in greater travel of the actuator tip. Gears Gears canbe used to increase travel ♦ Low force, low travel ♦ Moving parts arerequired ♦ IJ13 at the expense of duration. Circular actuators can beused ♦ Several actuator cycles are required gears, rack and pinion,ratchets, and ♦ Can be fabricated ♦ More complex drive electronics othergearing methods can be used. using standard surface ♦ Complexconstruction MEMS processes ♦ Friction, friction, and wear are possibleCatch The actuator controls a small catch. ♦ Very low actuator ♦ Complexconstruction ♦ IJ10 The catch either enables or disables energy ♦Requires external force movement of an ink pusher that is ♦ Very smallactuator ♦ Unsuitable for pigmented inks controlled in a bulk manner.size Buckle A buckle plate can be used to change ♦ Very fast movement ♦Must stay within elastic limits of the ♦ S. Hirata et al, “An plate aslow actuator into a fast motion. It achievable materials for longdevice life Ink-jet Head . . . ”, can also convert a high force, low ♦High stresses involved Proc. IEEE MEMS, travel actuator into a hightravel, ♦ Generally high power requirement Feb. 1996, pp 418- mediumforce motion. 423. ♦ IJ18, IJ27 Tapered A tapered magnetic pole canincrease ♦ Linearizes the ♦ Complex construction ♦ IJ14 magnetic travelat the expense of force. magnetic force/ pole distance curve Lever Alever and fulcrum is used to ♦ Matches low travel ♦ High stress aroundthe fulcrum ♦ IJ32, IJ36, IJ37 transform a motion with small travelactuator with higher and high force into a motion with travelrequirements longer travel and lower force. The ♦ Fulcrum area has nolever can also reverse the direction of linear movement, and travel. canbe used for a fluid seal Rotary The actuator is connected to a rotary ♦High mechanical ♦ Complex construction ♦ IJ28 impeller impeller. A smallangular defection advantage ♦ Unsuitable for pigmented inks of theactuator results in a rotation of ♦ The ratio of force the impellervanes, which push the to travel of the ink against stationary vanes andout actuator can be of the nozzle. matched to the nozzle requirements byvarying the number of impeller vanes Acoustic A refractive ordiffractive (e.g. zone ♦ No moving parts ♦ Large area required ♦ 1993Hadimioglu et lens plate) acoustic lens is used to ♦ Only relevant foracoustic ink jets al, EUP 550,192 concentrate sound waves. ♦ 1993 Elrodet al, EUP 572,220 Sharp A sharp point is used to concentrate ♦ Simpleconstruction ♦ Difficult to fabricate using standard ♦ Tone-jetconductive an electrostatic field. VLSI processes for a surface ejectingpoint ink-jet ♦ Only relevant for eletrostatic ink jets

ACTUATOR MOTION Actuator motion Description Advantages DisadvantagesExamples Volume The volume of the actuator changes, ♦ Simpleconstruction ♦ High energy is typically required to ♦ Hewlett-Packardexpansion pushing the ink in all directions. in the case of achievevolume expansion. This leads Thermal Inkjet thermal ink jet to thermalstress, cavitation, and ♦ Canon Bubblejet kogation in thermal ink jetimplementations Linear, The actuator moves in a direction ♦ Efficientcoupling High fabrication complexity may be ♦ IJ01, IJ02, IJ04, normalnormal to the print head surface. The to ink drops required to achieveperpendicular ♦ IJ11, IJ14 to chip nozzle is typically in the line ofejected normal to motion surface movement. the surface Linear, Theactuator moves parallel to the ♦ Suitable for planar ♦ Fabricationcomplexity ♦ IJ12, IJ13, IJ15, IJ33, parallel print head surface. Dropejection fabrication ♦ Friction ♦ IJ34, IJ35, IJ36 to chip may still benormal to the surface. ♦ Striction surface Membrane An actuator with ahigh force but ♦ The effective area ♦ Fabrication complexity ♦ 1982Hawkins U.S. push small area is used to push a stiff of the actuator ♦Actuator size Pat. No. 4,459,601 membrane that is in contact with thebecomes the ♦ Difficulty of integration in a VLSI ink. membrane areaprocess Rotary The actuator causes the rotation of ♦ Rotary levers may ♦Device complexity ♦ IJ05, IJ08, IJ13, IJ28 some element, such a grill orbe used to increase ♦ May have friction at a pivot point impeller travel♦ Small chip area requirements Bend The actuator bends when energized. ♦A very small change ♦ Requires the actuator to be made from ♦ 1970 Kyseret al U.S. This may be due to differential in dimensions at least twodistinct layers, or to have a Pat. No. 3,946,398 thermal expansion,piezoelectric can be converted thermal difference across the actuator ♦1973 Stemme U.S. expansion, magnetostriction, or other to a largemotion. Pat. No. 3,747,120 form of relative dimensional change. ♦ IJ03,IJ09, IJ10, IJ19 ♦ IJ23, IJ24, IJ25, IJ29 ♦ IJ30, IJ31, IJ33, IJ34 ♦IJ35 Swivel The actuator swivels around a central ♦ Allows operation ♦Inefficient coupling to the ink motion ♦ IJ06 pivot. This motion issuitable where where the net linear there are opposite forces applied toforce on the opposite sides of the paddle, e.g. paddle is zero. Lorenzforce. ♦ Small chip area requirements Straighten The actuator isnormally bent, and ♦ Can be used with ♦ Requires careful balance ofstresses to ♦ IJ26, IJ32 straightens when energized. shape memory ensurethat the quiescent bend is alloys where the accurate austenic phase isplanar Double The actuator bends in one direction ♦ One actuator can be♦ Difficult to make the drops ejected by ♦ IJ36, IJ37, IJ38 bend whenone element is energized, and used to power two both bend directionsidentical. bends the other way when another nozzles. ♦ A smallefficiency loss compared to element is energized. ♦ Reduced chip size.equivalent single bend actuators. ♦ Not sensitive to ambient temperatureShear Energizing the actuator causes a ♦ Can increase the ♦ Not readilyapplicable to other actuator ♦ 1985 Fishbeck U.S. shear motion in theactuator material. effective travel of mechanisms Pat. No. 4,584,590piezoelectric actuators Radial The actuator squeezes an ink ♦ Relativelyeasy to ♦ High force required ♦ 1970 Zoltan U.S. con- reservoir, forcingink from a fabricate single ♦ Inefficient Pat. No. 3,683,212 strictionconstricted nozzle. nozzles from glass ♦ Difficult to integrate withVLSI tubing as macro- processes scopic structures Coil/ A coiledactuator uncoils or coils ♦ Easy to fabricate ♦ Difficult to fabricatefor non-planar ♦ IJ17, IJ21, IJ34, IJ35 uncoil more tightly. The motionof the free as a planar devices end of the actuator ejects the ink. VLSIprocess ♦ Poor out-of-plane stiffness ♦ Small area required, thereforelow cost Bow The actuator bows (or buckles) in the ♦ Can increase the ♦Maximum travel is constrained ♦ IJ16, IJ18, 1127 middle when energized.speed of travel ♦ High force required ♦ Mechanically rigid Push-Pull Twoactuators control a shutter. One ♦ The structure is ♦ Not readilysuitable for inkjets which ♦ IJ18 actuator pulls the shutter, and thepinned at both ends, directly push the ink other pushes it. so has ahigh out-of- plane rigidity Curl A set of actuators curl inwards to ♦Good fluid flow to ♦ Design complexity ♦ IJ20, IJ42 inwards reduce thevolume of ink that they the region behind enclose. the actuator in-creases efficiency Curl A set of actuators curl outwards, ♦ Relativelysimple ♦ Relatively large chip area ♦ IJ43 outwards pressurizing ink ina chamber construction surrounding the actuators, and expelling ink froma nozzle in the chamber. Iris Multiple vanes enclose a volume of ♦ Highefficiency ♦ High fabrication complexity ♦ IJ22 ink. Thesesimultaneously rotate, ♦ Small chip area ♦ Not suitable for pigmentedinks reducing the volume between the vanes. Acoustic The actuatorvibrates at a high ♦ The actuator can be ♦ Large area required forefficient ♦ 1993 Hadimioglu vibration frequency. physically distantoperation at useful frequencies et al, EUP 550,192 from the ink ♦Acoustic coupling and crosstalk ♦ 1993 Elrod et al, EUP ♦ Complex drivecircuitry 572,220 ♦ Poor control of drop volume and position None Invarious inkjet designs the actuator ♦ No moving parts ♦ Various othertradeoffs are required to ♦ Silverbrook, EP 0771 does not move.eliminate moving parts 658 A2 and related patent applications ♦ Tone-jet

NOZZLE REFILL METHOD Nozzle refill method Description AdvantagesDisadvantages Examples Surface After the actuator is energized, it ♦Fabrication simplicity ♦ Low speed ♦ Thermal inkjet tension typicallyreturns rapidly to its normal ♦ Operational simplicity ♦ Surface tensionforce relatively ♦ Piezoelectric inkjet position. This rapid returnsucks in small compared to actuator force ♦ IJ01-IJ07, IJ10-IJ14 airthrough the nozzle opening. The ♦ Long refill time usually ♦ IJ16, IJ20,IJ22-IJ45 ink surface tension at the nozzle then dominates the totalrepetition exerts a small force restoring the rate meniscus to a minimumarea. Shuttered Ink to the nozzle chamber is ♦ High-speed ♦ Requirescommon ink pressure ♦ IJ08, IJ13, IJ15, IJ17 oscillating provided at apressure that oscillates ♦ Low actuator energy, as the oscillator ♦IJ18, IJ19, IJ21 ink at twice the drop ejection frequency. actuator needonly open or ♦ May not be suitable for pressure When a drop is to beejected, the close the shutter, instead of pigmented inks shutter isopened for 3 half cycles: ejecting the ink drop drop ejection, actuatorreturn, and refill. Refill After the main actuator has ejected a ♦ Highspeed, as the nozzle is ♦ Requires two independent ♦ IJ09 actuator dropa second (refill) actuator is actively refilled actuators per nozzleenergized. The refill actuator pushes ink into the nozzle chamber. Therefill actuator returns slowly, to prevent its return from emptying thechamber again. Positive The ink is held a slight positive ♦ High refillrate, therefore a ♦ Surface spill must be prevented ♦ Silverbrook, EP0771 ink pressure. After the ink drop is high drop repetition rate is ♦Highly hydrophobic print head 658 A2 and related pressure ejected, thenozzle chamber fills possible surfaces are required patent applicationsquickly as surface tension and ink ♦ Alternative for: pressure bothoperate to refill the ♦ IJ01-IJ07, IJ10-IJ14 nozzle. ♦ IJ16, IJ20,IJ22-IJ45

METHOD OF RESTRICTING BACK-FLOW THROUGH INLET Inlet back-flowrestriction method Description Advantages Disadvantages Examples Longinlet The ink inlet channel to the nozzle ♦ Design simplicity ♦Restricts refill rate ♦ Thermal inkjet channel chamber is made long andrelatively ♦ Operational simplicity ♦ May result in a relatively largechip ♦ Piezoelectric inkjet narrow, relying on viscous drag to ♦ Reducescrosstalk area ♦ IJ42, IJ43 reduce inlet back-flow. ♦ Only partiallyeffective Positive The ink is under a positive pressure, ♦ Dropselection and ♦ Requires a method (such as a nozzle ♦ Silverbrook, EP0771 ink so that in the quiescent state some of separation forces canrim or effective hydrophobizing, or 658 A2 and related pressure the inkdrop already protrudes from be reduced both) to prevent flooding of thepatent applications the nozzle. ♦ Fast refill time ejection surface ofthe print head. ♦ Possible operation of This reduces the pressure in thethe following: nozzle chamber which is required to ♦ IJ01-IJ07,IJ09-IJ12 eject a certain volume of ink. The ♦ IJ14, IJ16, IJ20, IJ22,reduction in chamber pressure results ♦ IJ23-IJ34, IJ36-IJ41 in areduction in ink pushed out ♦ IJ44 through the inlet. Baffle One or morebaffles are placed in the ♦ The refill rate is not as ♦ Designcomplexity ♦ HP Thermal Ink Jet inlet ink flow. When the actuator isrestricted as the long ♦ May increase fabrication complexity ♦ Tektronixenergized, the rapid ink movement inlet method. (e.g. Tektronix hot meltPiezoelectric piezoelectric ink jet creates eddies which restrict theflow ♦ Reduces crosstalk print heads). through the inlet. The slowerrefill process is unrestricted, and does not result in eddies. FlexibleIn this method recently disclosed by ♦ Significantly reduces ♦ Notapplicable to most inkjet ♦ Canon flap Canon, the expanding actuatorback-flow for edge- configurations restricts (bubble) pushes on aflexible flap shooter thermal ink jet ♦ Increased fabrication complexityinlet that restricts the inlet. devices ♦ Inelastic deformation ofpolymer flap results in creep over extended use Inlet filter A filter islocated between the ink ♦ Additional advantage ♦ Restricts refill rate ♦IJ04, IJ12, IJ24, IJ27 inlet and the nozzle chamber. The of inkfiltration ♦ May result in complex construction ♦ IJ29, IJ30 filter hasa multitude of small holes ♦ Ink filter may be or slots, restricting inkflow. The fabricated with no filter also removes particles whichadditional process may block the nozzle. steps Small inlet The ink inletchannel to the nozzle ♦ Design simplicity ♦ Restricts refill rate ♦IJ02, IJ37, IJ44 compared chamber has a substantially smaller ♦ Mayresult in a relatively large chip to nozzle cross section than that ofthe nozzle, area resulting in easier ink egress out of ♦ Only partiallyeffective the nozzle than out of the inlet. Inlet A secondary actuatorcontrols the ♦ Increases speed of the ♦ Requires separate refillactuator and ♦ IJ09 shutter position of a shutter, closing off theink-jet print head drive circuit ink inlet when the main actuator isoperation energized. The inlet The method avoids the problem of ♦Back-flow problem is ♦ Requires careful design to minimize ♦ IJ01, IJ03,IJ05, IJ06 is located inlet back-flow by arranging the ink- eliminatedthe negative pressure behind the ♦ IJ07, IJ10, IJ11, IJ14 behind thepushing surface of the actuator paddle ♦ IJ16, IJ22, IJ23, IJ25 ink-between the inlet and the nozzle. ♦ IJ28, IJ31, IJ32, IJ33 pushing ♦IJ34, IJ35, IJ36, IJ39 surface ♦ IJ40, IJ41 Part of The actuator and awall of the ink ♦ Significant reductions ♦ Small increase in fabrication♦ IJ07, IJ20, IJ26, IJ38 the chamber are arranged so that the inback-flow can be complexity actuator motion of the actuator closes offthe achieved moves to inlet. ♦ Compact designs shut off possible theinlet Nozzle In some configurations of ink jet, ♦ Ink back-flow problem♦ None related to ink back-flow on ♦ Silverbrook, EP 0771 actuator thereis no expansion or movement is eliminated actuation 658 A2 and relateddoes not of an actuator which may cause ink patent applications resultin back-flow through the inlet. ♦ Valve-jet ink ♦ Tone-jet back-flow ♦IJ08, IJ13, IJ15, IJ17 ♦ IJ18, IJ19, IJ21

NOZZLE CLEARING METHOD Nozzle Clearing method Description AdvantagesDisadvantages Examples Normal All of the nozzles are fired ♦ No addedcomplexity ♦ May not be sufficient to displace ♦ Most ink jet systemsnozzle periodically, before the ink has a on the print head dried ink ♦IJ01-IJ07, IJ09-IJ12 firing chance to dry. When not in use the ♦ IJ14,IJ16, IJ20, IJ22 nozzles are sealed (capped) against ♦ IJ23-IJ34,IJ36-IJ45 air. The nozzle firing is usually performed during a specialclearing cycle, after first moving the print head to a cleaning station.Extra In systems which heat the ink, but do ♦ Can be highly ♦ Requireshigher drive voltage for ♦ Silverbrook, EP 0771 power to not boil itunder normal situations, effective if the heater clearing 658 A2 andrelated ink heater nozzle clearing can be achieved by is adjacent to the♦ May require larger drive transistors patent applications over-poweringthe heater and boiling nozzle ink at the nozzle. Rapid The actuator isfired in rapid ♦ Does not require extra ♦ Effectiveness dependssubstantially ♦ May be used with succession succession. In someconfigurations, drive circuits on the upon the configuration of theinkjet ♦ IJ01-IJ07, IJ09-IJ11 of actuator this may cause heat build-upat the print head nozzle ♦ IJ14, IJ16, IJ20, IJ22 pulses nozzle whichboils the ink, clearing ♦ Can be readily ♦ IJ23-IJ25, IJ27-IJ34 thenozzle. In other situations, it may controlled and initiated ♦ IJ36-IJ45cause sufficient vibrations to by digital logic dislodge cloggednozzles. Extra Where an actuator is not normally A simple solution ♦ Notsuitable where there is a ♦ May be used with power to driven to thelimit of its motion, where applicable hard limit to actuator movement ♦IJ03, IJ09, IJ16, IJ20 ink nozzle clearing may be assisted by ♦ IJ23,IJ24, IJ25, IJ27 pushing providing an enhanced drive signal ♦ IJ29,IJ30, IJ31, IJ32 actuator to the actuator. ♦ IJ39, IJ40, IJ41, IJ42 ♦IJ43, IJ44, IJ45 Acoustic An ultrasonic wave is applied to the ♦ A highnozzle clearing ♦ High implementation cost if system ♦ IJ08, IJ13, IJ15,IJ17 resonance ink chamber. This wave is of an capability can be doesnot already include an acoustic ♦ IJ18, IJ19, IJ21 appropriate amplitudeand frequency achieved actuator to cause sufficient force at the nozzle♦ May be implemented to clear blockages. This is easiest to at very lowcost in achieve if the ultrasonic wave is at a systems which alreadyresonant frequency of the ink cavity. include acoustic actuators NozzleA microfabricated plate is pushed ♦ Can clear severely ♦ Accuratemechanical alignment is ♦ Silverbrook, EP 0771 clearing against thenozzles. The plate has a clogged nozzles required 658 A2 and relatedplate post for every nozzle. The array of ♦ Moving parts are requiredpatent applications posts ♦ There is risk of damage to the nozzles ♦Accurate fabrication is required Ink The pressure of the ink is ♦ May beeffective ♦ Requires pressure pump or other ♦ May be used with allpressure temporarily increased so that ink where other methods pressureactuator IJ series inkjets pulse streams from all of the nozzles. Thiscannot be used ♦ Expensive may be used in conjunction with ♦ Wasteful ofink actuator energizing. Print head A flexible ‘blade’ is wiped acrossthe ♦ Effective for planar ♦ Difficult to use if print head surface ♦Many ink jet systems wiper print head surface. The blade is print headsurfaces is non-planar or very fragile usually fabricated from aflexible ♦ Low cost ♦ Requires mechanical parts polymer, e.g. rubber orsynthetic ♦ Blade can wear out in high volume elastomer. print systemsSeparate A separate heater is provided at the ♦ Can be effective ♦Fabrication complexity ♦ Can be used with ink boiling nozzle althoughthe normal drop ejec- where other nozzle many IJ series ink heater tionmechanism does not require it. clearing methods jets The heaters do notrequire individual cannot be used drive circuits, as many nozzles can ♦Can be implemented at be cleared simultaneously, and no no additionalcost imaging is required. in some ink jet configurations

NOZZLE PLATE CONSTRUCTION Nozzle plate construc- tion DescriptionAdvantages Disadvantages Examples Electro- A nozzle plate is separately♦ Fabrication simplicity ♦ High temperatures and pressures are ♦ HewlettPackard formed fabricated from electroformed nickel, required to bondnozzle plate Thermal Inkjet nickel and bonded to the print head chip. ♦Minimum thickness constraints ♦ Differential thermal expansion LaserIndividual nozzle holes are ablated ♦ No masks required ♦ Each hole mustbe individually ♦ Canon Bubblejet ablated or by an intense UV laser in anozzle ♦ Can be quite fast formed ♦ 1988 Sercel et al., drilled plate,which is typically a polymer ♦ Some control over ♦ Special equipmentrequired SPIE, Vol. 998 polymer such as polyimide or polysulphone nozzleprofile is ♦ Slow where there are many thousands Excimer Beam possibleof nozzles per print head applications, pp. ♦ Equipment required is ♦May produce thin burrs at exit holes 76-83 relatively low cost ♦ 1993Watanabe et al., U.S. Pat. No. 5,208,604 Silicon A separate nozzle plateis ♦ High accuracy is ♦ Two part construction ♦ K. Bean, IEEE micro-micromachined from single crystal attainable ♦ High cost Transactions onmachined silicon, and bonded to the print head ♦ Requires precisionalignment Electron Devices, wafer. ♦ Nozzles may be clogged by adhesiveVol. ED-25, No 10, 1978, pp 1185-1195 ♦ Xerox 1990 Hawkins et al., U.S.Pat. No. 4,899,181 Glass Fine glass capillaries are drawn from ♦ Noexpensive equip- ♦ Very small nozzle sizes are difficult ♦ 1970 ZoltanU.S. capillaries glass tubing. This method has been ment required toform Pat. No. 3,683,212 used for making individual nozzles, ♦ Simple tomake single ♦ Not suited for mass production but is difficult to use forbulk nozzles manufacturing of print heads with thousands of nozzles.Mono- The nozzle plate is deposited as a ♦ High accuracy (<1 μm) ♦Requires sacrificial layer under the ♦ Silverbrook, EP 0771 lithic,layer using standard VLSI deposition ♦ Monolithic nozzle plate to formthe nozzle 658 A2 and related surface techniques. Nozzles are etched inthe ♦ Low cost chamber patent applications micro- nozzle plate usingVLSI lithography ♦ Existing processes can ♦ Surface may be fragile tothe touch ♦ IJ01, IJ02, IJ04, IJ11 machined and etching. be used ♦ IJ12,IJ17, IJ18, IJ20 using ♦ IJ22, IJ24, IJ27, IJ28 VLSI ♦ IJ29, IJ30, IJ31,IJ32 litho- ♦ IJ33, IJ34, IJ36, IJ37 graphic ♦ IJ38, IJ39, IJ40, IJ41processes ♦ IJ42, IJ43, IJ44 Mono- The nozzle plate is a buried etchstop ♦ High accuracy (<1 μm) ♦ Requires long etch times ♦ IJ03, IJ05,IJ06, IJ07 lithic, in the wafer. Nozzle chambers are ♦ Monolithic ♦Requires a support wafer ♦ IJ08, IJ09, IJ10, IJ13 etched etched in thefront of the wafer, and ♦ Low cost ♦ IJ14, IJ15, IJ16, IJ19 through thewafer is thinned from the back ♦ No differential ♦ IJ21, IJ23, IJ25,IJ26 substrate side. Nozzles are then etched in the expansion etch stoplayer. No nozzle Various methods have been tried to ♦ No nozzles tobecome ♦ Difficult to control drop position ♦ Ricoh 1995 Sekiya plateeliminate the nozzles entirely, to clogged accurately et al U.S. Pat.No. prevent nozzle clogging. These ♦ Crosstalk problems 5,412,413include thermal bubble mechanisms ♦ 1993 Hadimioglu et al and acousticlens mechanisms EUP 550,192 ♦ 1993 Elrod et al EUP 572,220 Trough Eachdrop ejector has a trough ♦ Reduced manufac- ♦ Drop firing direction issensitive to ♦ IJ35 through which a paddle moves. turing complexitywicking. There is no nozzle plate. ♦ Monolithic Nozzle slit Theelimination of nozzle holes and ♦ No nozzles to become ♦ Difficult tocontrol drop position ♦ 1989 Saito et al U.S. instead of replacement bya slit encompassing clogged accurately Pat. No. 4,799,068 individualmany actuator positions reduces ♦ Crosstalk problems nozzles nozzleclogging, but increases crosstalk due to ink surface waves

DROP EJECTION DIRECTION Ejection direction Description AdvantagesDisadvantages Examples Edge Ink flow is along the surface of ♦ Simpleconstruction ♦ Nozzles limited to edge ♦ Canon Bubblejet (‘edge thechip, and ink drops are ♦ No silicon etching required ♦ High resolutionis difficult 1979 Endo et al GB shooter’) ejected from the chip edge. ♦Good heat sinking via ♦ Fast color printing requires one print patentNo. 2,007,262 substrate head per color ♦ Xerox heater-in-pit ♦Mechanically strong 1990 Hawkins et al ♦ Ease of chip handing U.S. Pat.No. 4,899,181 ♦ Tone-jet Surface Ink flow is along the surface of ♦ Nobulk silicon etching ♦ Maximum ink flow is severely ♦ Hewlett-PackardTIJ (‘roof the chip, and ink drops are required restricted 1982 Vaughtet al shooter’) ejected from the chip surface, ♦ Silicon can make anU.S. Pat. No. normal to the plane of the chip. effective heat sink4,490,728 ♦ Mechanical strength ♦ IJ02, IJ11, IJ12, IJ20 ♦ IJ22 ThroughInk flow is through the chip, and ♦ High ink flow ♦ Requires bulksilicon etching ♦ Silverbrook, EP 0771 chip, ink drops are ejected fromthe ♦ Suitable for pagewidth print 658 A2 and related forward frontsurface of the chip. ♦ High nozzle packing patent applications (‘updensity therefore low ♦ IJ04, IJ17, IJ18, IJ24 shooter’) manufacturingcost ♦ IJ27-IJ45 Through Ink flow is through the chip, and ♦ High inkflow ♦ Requires wafer thinning ♦ IJ01, IJ03, IJ05, IJ06, chip, ink dropsare ejected from the ♦ Suitable for pagewidth print ♦ Requires specialhandling during ♦ IJ07, IJ08, 1109, IJ10 reverse rear surface of thechip. ♦ High nozzle packing manufacture ♦ IJ13, IJ14, IJ15, IJ16 (‘downdensity therefore low ♦ IJ19, IJ22, IJ23, IJ25 shooter’) manufacturingcost ♦ IJ26 Through Ink flow is through the actuator, ♦ Suitable forpiezoelectric ♦ Pagewidth print heads require several ♦ Epson Stylusactuator which is not fabricated as part print heads thousandconnections to drive circuits ♦ Tektronix hot melt of the same substrateas the ♦ Cannot be manufactured in standard piezoelectric ink jets drivetransistors. CMOS fabs ♦ Complex assembly required

INK TYPE Ink type Description Advantages Disadvantages Examples Aqueous,Water based ink which typically ♦ Environmentally ♦ Slow drying ♦ Mostexisting inkjets dye contains: water, dye, surfactant, friendly ♦Corrosive ♦ All IJ series ink jets humectant, and biocide. ♦ No odor ♦Bleeds on paper ♦ Silverbrook, EP 0771 Modern ink dyes have high water-♦ May strikethrough 658 A2 and related fastness, light fastness ♦Cockles paper patent applications Aqueous, Water based ink whichtypically ♦ Environmentally ♦ Slow drying IJ02, IJ04, IJ21, IJ26 pigmentcontains: water, pigment, friendly ♦ Corrosive IJ27, IJ30 surfactant,humectant, and ♦ No odor ♦ Pigment may clog nozzles ♦ Silverbrook, EP0771 biocide. Pigments have an ♦ Reduced bleed ♦ Pigment may clogactuator 658 A2 and related advantage in reduced bleed, ♦ Reducedwicking mechanisms patent applications wicking and strikethrough. ♦Reduced strikethrough ♦ Cockles paper ♦ Piezoelectric ink-jets ♦ Thermalink jets (with significant restrictions) Methyl MEK is a highly volatilesolvent ♦ Very fast drying ♦ Odorous ♦ All IJ series ink jets Ethyl usedfor industrial printing on ♦ Prints on various ♦ Flammable Ketonedifficult surfaces such as aluminum substrates such as (MEK) cans.metals and plastics Alcohol Alcohol based inks can be used Fast drying ♦Slight odor ♦ All IJ series ink jet (ethanol, where the printer mustoperate at ♦ Operates at sub- ♦ Flammable 2-butanol, temperatures belowthe freezing freezing temperatures and point of water. An example ofthis ♦ Reduced paper cockle others) is in-camera consumer photo- ♦ Lowcost graphic printing. Phase The ink is solid at room tempera- ♦ Nodrying time - ink ♦ High viscosity ♦ Tektronix hot melt change ture, andis melted in the print head instantly freezes on ♦ Printed ink typicallyhas a ‘waxy’ feel piezoelectric ink jets (hot melt) before jetting. Hotmelt inks are the print medium ♦ Printed pages may ‘block’ ♦ 1989 NowakU.S. usually wax based, with a melting ♦ Almost any print ♦ Inktemperature maybe above the Pat. No. 4,820,346 point around 80° C. Afterjetting medium can be used curie point of permanent magnets All IJseries inkjets the ink freezes almost instantly ♦ No paper cockle ♦ Inkheaters consume power upon contacting the print medium occurs ♦ Longwarm-up time or a transfer roller. ♦ No wicking occurs ♦ No bleed occurs♦ No strikethrough occurs Oil Oil based inks are extensively used ♦ Highsolubility ♦ High viscosity: this is a significant ♦ All IJ series inkjets in offset printing. They have medium for some dyes limitation foruse in inkjets, which advantages in improved ♦ Does not cockle paperusually require a low viscosity. Some characteristics on paper(especially ♦ Does not wick through short chain and multi-branched oilsno wicking or cockle). Oil soluble paper have a sufficiently lowviscosity. dies and pigments are required. ♦ Slow drying Micro- Amicroemulsion is a stable, self ♦ Stops ink bleed ♦ Viscosity higherthan water ♦ All IJ series ink jets emulsion forming emulsion of oil,water, and ♦ High dye solubility ♦ Cost is slightly higher than waterbased surfactant. The characteristic drop ♦ Water, oil, and ink size isless than 100 nm, and is amphiphilic soluble ♦ High surfactantconcentration required determined by the preferred dies can be used(around 5%) curvature of the surfactant. ♦ Can stabilize pigmentsuspensions

Ink Jet Printing

A large number of new forms of ink jet printers have been developed tofacilitate alternative ink jet technologies for the image processing anddata distribution system. Various combinations of ink jet devices can beincluded in printer devices incorporated as part of the presentinvention. Australian Provisional Patent Applications relating to theseink jets which are specifically incorporated by cross reference include:

Australian Provisional Number Filing Date Title PO8066 15-Jul-97 ImageCreation Method and Apparatus (IJ01) PO8072 15-Jul-97 Image CreationMethod and Apparatus (IJ02) PO8040 15-Jul-97 Image Creation Method andApparatus (IJ03) PO8071 15-Jul-97 Image Creation Method and Apparatus(IJ04) PO8047 15-Jul-97 Image Creation Method and Apparatus (IJ05)PO8035 15-Jul-97 Image Creation Method and Apparatus (IJ06) PO804415-Jul-97 Image Creation Method and Apparatus (IJ07) PO8063 15-Jul-97Image Creation Method and Apparatus (IJ08) PO8057 15-Jul-97 ImageCreation Method and Apparatus (IJ09) PO8056 15-Jul-97 Image CreationMethod and Apparatus (IJ10) PO8069 15-Jul-97 Image Creation Method andApparatus (IJ11) PO8049 15-Jul-97 Image Creation Method and Apparatus(IJ12) PO8036 15-Jul-97 Image Creation Method and Apparatus (IJ13)PO8048 15-Jul-97 Image Creation Method and Apparatus (IJ14) PO807015-Jul-97 Image Creation Method and Apparatus (IJ15) PO8067 15-Jul-97Image Creation Method and Apparatus (IJ16) PO8001 15-Jul-97 ImageCreation Method and Apparatus (IJ17) PO8038 15-Jul-97 Image CreationMethod and Apparatus (IJ18) PO8033 15-Jul-97 Image Creation Method andApparatus (IJI9) PO8002 15-Jul-97 ImageCreation Method and Apparatus(IJ20) PO8068 15-Jul-97 Image Creation Method and Apparatus (IJ21)PO8062 15-Jul-97 Image Creation Method and Apparatus (IJ22) PO803415-Jul-97 Image Creation Method and Apparatus (IJ23) PO8039 15-Jul-97Image Creation Method and Apparatus (IJ24) PO8041 15-Jul-97 ImageCreation Method and Apparatus (IJ25) PO8004 15-Jul-97 Image CreationMethod and Apparatus (IJ26) PO8037 15-Jul-97 Image Creation Method andApparatus (IJ27) PO8043 15-Jul-97 Image Creation Method and Apparatus(IJ28) PO8042 15-Jul-97 Image Creation Method and Apparatus (IJ29)PO8064 15-Jul-97 Image Creation Method and Apparatus (IJ30) PO938923-Sep-97 Image Creation Method and Apparatus (IJ31) PO9391 23-Sep-97Image Creation Method and Apparatus (IJ32) PP0888 12-Dec-97 ImageCreation Method and Apparatus (IJ33) PP0891 12-Dec-97 Image CreationMethod and Apparatus (IJ34) PP0890 12-Dec-97 Image Creation Method andApparatus (IJ35) PP0873 12-Dec-97 Image Creation Method and Apparatus(IJ36) PP0993 12-Dec-97 Image Creation Method and Apparatus (IJ37)PP0890 12-Dec-97 Image Creation Method and Apparatus (IJ38) PP139819-Jan-98 An Image Creation Method and Apparatus (IJ39) PP2592 25-Mar-98An Image Creation Method and Apparatus (IJ40) PP593 25-Mar-98 ImageCreation Method and Apparatus (IJ41) PP3991 9-Jun-98 Image CreationMethod and Apparatus (IJ42) PP3987 9-Jun-98 Image Creation Method andApparatus (IJ43) PP3985 9-Jun-98 Image Creation Method and Apparatus(IJ44) PP3983 9-Jun-98 Image Creation Method and Apparatus (IJ45)

Ink Jet Manufacturing

Further, the present application may utilize advanced semiconductorfabrication techniques in the construction of large arrays of ink jetprinters. Suitable manufacturing techniques are described in thefollowing Australian provisional patent specifications incorporated hereby cross-reference:

Australian Provisional Number Filing Date Title PO7935 15-Jul-97 AMethod of Manufacture of an Image Creation Apparatus (IJM01) PO793615-Jul-97 A Method of Manufacture of an Image Creation Apparatus (IJM02)PO7937 15-Jul-97 A Method of Manufacture of an Image Creation Apparatus(IJM03) PO8061 15-Jul-97 A Method of Manufacture of an Image CreationApparatus (IJM04) PO8054 15-Jul-97 A Method of Manufacture of an ImageCreation Apparatus (IJM05) PO8065 15-Jul-97 A Method of Manufacture ofan Image Creation Apparatus (IJM06) PO8055 15-Jul-97 A Method ofManufacture of an Image Creation Apparatus (IJM07) PO8053 15-Jul-97 AMethod of Manufacture of an Image Creation Apparatus (IJM08) PO807815-Jul-97 A Method of Manufacture of an Image Creation Apparatus (IJM09)PO7933 15-Jul-97 A Method of Manufacture of an Image Creation Apparatus(IJM10) PO7950 15-Jul-97 A Method of Manufacture of an Image CreationApparatus (IJM11) PO7949 15-Jul-97 A Method of Manufacture of an ImageCreation Apparatus (IJM12) PO8060 15-Jul-97 A Method of Manufacture ofan Image Creation Apparatus (IJM13) PO8059 15-Jul-97 A Method ofManufacture of an Image Creation Apparatus (IJM14) PO8073 15-Jul-97 AMethod of Manufacture of an Image Creation Apparatus (IJM15) PO807615-Jul-97 A Method of Manufacture of an Image Creation Apparatus (IJM16)PO8075 15-Jul-97 A Method of Manufacture of an Image Creation Apparatus(IJM17) PO8079 15-Jul-97 A Method of Manufacture of an Image CreationApparatus (IJM18) PO8050 15-Jul-97 A Method of Manufacture of an ImageCreation Apparatus (IJM19) PO8052 15-Jul-97 A Method of Manufacture ofan Image Creation Apparatus (IJM20) PO7948 15-Jul-97 A Method ofManufacture of an Image Creation Apparatus (IJM21) PO7951 15-Jul-97 AMethod of Manufacture of an Image Creation Apparatus (IJM22) PO807415-Jul-97 A Method of Manufacture of an Image Creation Apparatus (IJM23)PO7941 15-Jul-97 A Method of Manufacture of an Image Creation Apparatus(IJM24) PO8077 15-Jul-97 A Method of Manufacture of an Image CreationApparatus (IJM25) PO8058 15-Jul-97 A Method of Manufacture of an ImageCreation Apparatus (IJM26) PO8051 15-Jul-97 A Method of Manufacture ofan Image Creation Apparatus (IJM27) PO8045 15-Jul-97 A Method ofManufacture of an Image Creation Apparatus (IJM28) PO7952 15-Jul-97 AMethod of Manufacture of an Image Creation Apparatus (IJM29) PO804615-Jul-97 A Method of Manufacture of an Image Creation Apparatus (IJM30)PO8503 11-Aug-97 A Method of Manufacture of an Image Creation Apparatus(IJM30a) PO9390 23-Sep-97 A Method of Manufacture of an Image CreationApparatus (IJM31) PO9392 23-Sep-97 A Method of Manufacture of an ImageCreation Apparatus (IJM32) PP0889 12-Dec-97 A Method of Manufacture ofan Image Creation Apparatus (IJM35) PP0887 12-Dec-97 A Method ofManufacture of an Image Creation Apparatus (IJM36) PP0882 12-Dec-97 AMethod of Manufacture of an Image Creation Apparatus (IJM37) PP087412-Dec-97 A Method of Manufacture of an Image Creation Apparatus (IJM38)PP1396 19-Jan-98 A Method of Manufacture of an Image Creation Apparatus(IJM39) PP2591 25-Mar-98 A Method of Manufacture of an Image CreationApparatus (IJM41) PP3989 9-Jun-98 A Method of Manufacture of an ImageCreation Apparatus (IJM40) PP3990 9-Jun-98 A Method of Manufacture of anImage Creation Apparatus (IJM42) PP3986 9-Jun-98 A Method of Manufactureof an Image Creation Apparatus (IJM43) PP3984 9-Jun-98 A Method ofManufacture of an Image Creation Apparatus (IJM44) PP3982 9-Jun-98 AMethod of Manufacture of an Image Creation Apparatus (IJM45)

Fluid Supply

Further, the present application may utilize an ink delivery system tothe ink jet head. Delivery systems relating to the supply of ink to aseries of ink jet nozzles are described in the following Australianprovisional patent specifications, the disclosure of which are herebyincorporated by cross-reference:

Australian Provisional Number Filing Date Title PO8003 15-Jul-97 SupplyMethod and Apparatus (F1) PO8005 15-Jul-97 Suppiy Method and Apparatus(F2) PO9404 23-Sep-97 A Device and Method (F3)

MEMS Technology

Further, the present application may utilize advanced semiconductormicroelectromechanical techniques in the construction of large arrays ofink jet printers. Suitable microelectromechanical techniques aredescribed in the following Australian provisional patent specificationsincorporated here by cross-reference:

Australian Provisional Number Filing Date Title PO7943 15-Jul-97 Adevice (MEMS01) PO8006 15-Jul-97 A device (MEMS02) PO8007 15-Jul-97 Adevice (MEMS03) PO8008 15-Jul-97 A device (MEMS04) PO8010 15-Jul-97 Adevice (MEMS05) PO8011 15-Jul-97 A device (MEMS06) P97947 15-Jul-97 Adevice (MEMS07) PO7945 15-Jul-97 A device (MEMS08) PO7944 15-Jul-97 Adevice (MEMS09) PO7946 15-Jul-97 A device (MEMS10) PO9393 23-Sep-97 ADevice and Method (MEMS11) PP0875 12-Dec-97 A Device (MEMS12) PP089412-Dec-97 A Device and Method (MEMS13)

IR Technologies

Further, the present application may include the utilization of adisposable camera system such as those described in the followingAustralian provisional patent specifications incorporated here bycross-reference:

Australian Provisional Number Filing Date Title PP0895 12-Dec-97 AnImage Creation Method and Apparatus (IR01) PP0870 12-Dec-97 A Device andMethod (IR02) PP0869 12-Dec-97 A Device and Method (IR04) PP088712-Dec-97 Image Creation Method and Apparatus (IR05) PP0885 12-Dec-97 AnImage Production System (IR06) PP0884 12-Dec-97 Image Creation Methodand Apparatus (IR10) PP0886 12-Dec-97 Image Creation Method andApparatus (IR12) PP0871 12-Dec-97 A Device and Method (IR13) PP087612-Dec-97 An Image Processing Method and Apparatus (IR14) PP087712-Dec-97 A Device and Method (IR16) PP0878 12-Dec-97 A Device andMethod (IR17) PP0879 12-Dec-97 A Device and Method (IR18) PP088312-Dec-97 A Device and Method (IRI9) PP0880 12-Dec-97 A Device andMethod (IR20) PP0881 12-Dec-97 A Device and Method (IR21)

DotCard Technologies

Further, the present application may include the utilization of a datadistribution system such as that described in the following Australianprovisional patent specifications incorporated here by cross-reference:

Australian Provisional Number Filing Date Title PP2370 16-Mar-98 DataProcessing Method and Apparatus (Dot01) PP2371 16-Mar-98 Data ProcessingMethod and Apparatus (Dot02)

Artcam Technologies

Further, the present application may include the utilization of cameraand data processing techniques such as an Artcam type device asdescribed in the following Australian provisional patent specificationsincorporated here by cross-reference:

Australian Provisional Number Filing Date Title PO7991 15-Jul-97 ImageProcessing Method and Apparatus (ART01) PO8505 11-Aug-97 ImageProcessing Method and Apparatus (ART01a) PO7998 15-Jul-97 ImageProcessing Method and Apparatus (ART02) PO7993 15-Jul-97 ImageProcessing Method and Apparatus (ART03) PO8012 15-Jul-97 ImageProcessing Method and Apparatus (ART05) PO8017 15-Jul-97 ImageProcessing Method and Apparatus (ART06) PO8014 15-Jul-97 Media Device(ART07) PO8025 15-Jul-97 Image Processing Method and Apparatus (ART08)PO8032 15-Jul-97 Image Processing Method and Apparatus (ART09) PO799915-Jul-97 Image Processing Method and Apparatus (ART10) PO7998 15-Jul-97Image Processing Method and Apparatus (ART11) PO8031 15-Jul-97 ImageProcessing Method and Apparatus (ART12) PO8030 15-Jul-97 Media Device(ART13) PO8498 11-Aug-97 Image Processing Method and Apparatus (ART14)PO7997 15-Jul-97 Media Device (ART15) PO7979 15-Jul-97 Media Device(ART16) PO8015 15-Jul-97 Media Device (ART17) PO7978 15-Jul-97 MediaDevice (ART18) PO7982 15-Jul-97 Data Processing Method and Apparatus(ART19) PO7989 15-Jul-97 Data Processing Method and Apparatus (ART20)P08019 15-Jul-97 Media Processing Method and Apparatus (ART21) PO798015-Jul-97 Image Processing Method and Apparatus (ART22) PO7942 15-Jul-97Image Processing Method and Apparatus (ART23) PO8018 15-Jul-97 ImageProcessing Method and Apparatus (ART24) PO7938 15-Jul-97 ImageProcessing Method and Apparatus (ART25) PO8016 15-Jul-97 ImageProcessing Method and Apparatus (ART26) PO8024 15-Jul-97 ImageProcessing Method and Apparatus (ART27) PO7940 15-Jul-97 Data ProcessingMethod and Apparatus (ART28) PO7939 15-Jul-97 Data Processing Method andApparatus (ART29) PO8501 11-Aug-97 Image Processing Method and Apparatus(ART30) PO8500 11-Aug-97 Image Processing Method and Apparatus (ART31)PO7987 15-Jul-97 Data Processing Method and Apparatus (ART32) PO802215-Jul-97 Image Processing Method and Apparatus (ART33) PO8497 11-Aug-97Image Processing Method and Apparatus (ART30) PO8029 15-Jul-97 SensorCreation Method and Apparatus (ART36) PO7985 15-Jul-97 Data ProcessingMethod and Apparatus (ART37) PO8020 15-Jul-97 Data Processing Method andApparatus (ART38) PO8023 15-Jul-97 Data Processing Method and Apparatus(ART39) PO9395 23-Sep-97 Data Processing Method and Apparatus (ART4)PO8021 15-Jul-97 Data Processing Method and Apparatus (ART40) PO850411-Aug-97 Image Processing Method and Apparatus (ART42) PO8000 15-Jul-97Data Processing Method and Apparatus (ART43) PO7977 15-Jul-97 DataProcessing Method and Apparatus (ART44) PO7934 15-Jul-97 Data ProcessingMethod and Apparatus (ART45) PO7990 15-Jul-97 Data Processing Method andApparatus (ART46) PO8499 11-Aug-97 Image Processing Method and Apparatus(ART47) PO8502 11-Aug-97 Image Processing Method and Apparatus (ART48)PO7981 15-Jul-97 Data Processing Method and Apparatus (ART50) PO798615-Jul-97 Data Processing Methodand Apparatus (ART51) PO7983 15-Jul-97Data Processing Method and Apparatus (ART52) PO8026 15-Jul-97 ImageProcessing Method and Apparatus (ART53) PO8027 15-Jul-97 ImageProcessing Method and Apparatus (ART54) PO8028 15-Jul-97 ImageProcessing Method and Apparatus (ART56) PO9394 23-Sep-97 ImageProcessing Method and Apparatus (ART57) PO9396 23-Sep-97 Data ProcessingMethod and Apparatus (ART58) PO9397 23-Sep-97 Data Processing Method andApparatus (ART59) PO9398 23-Sep-97 Data Processing Method and Apparatus(ART60) PO9399 23-Sep-97 Data Processing Method and Apparatus (ART61)PO9400 23-Sep-97 Data Processing Method and Apparatus (ART62) PO940123-Sep-97 Data Processing Method and Apparatus (ART63) PO9402 23-Sep-97Data Processing Method and Apparatus (ART64) PO9403 23-Sep-97 DataProcessing Method and Apparatus (ART65) PO9405 23-Sep-97 Data ProcessingMethod and Apparatus (ART66) PP0959 16-Dec-97 A Data Processing Methodand Apparatus (ART68) PP1397 19-Jan-98 A Media Device (ART69)

I claim:
 1. An apparatus for ejecting fluids from a nozzle chambercomprising: a nozzle chamber having at least two fluid ejectionapertures defined in the walls of said chamber; a moveable paddle vanelocated between said fluid ejection apertures; an actuator mechanismattached to said moveable paddle vane and adapted to move said paddlevane in a first direction so as to cause the ejection of fluid drops outof a first fluid ejection aperture and to further move said paddle vanein a second alternative direction so as to cause the ejection of fluiddrops out of a second fluid ejection aperture.
 2. An apparatus asclaimed in claim 1 wherein said actuator comprises a thermal actuatorhaving at least two heater elements with a first of said elements beingactuated to cause said paddle vane to move in a first direction and asecond heater element being actuated to cause said paddle vane to movein a second direction.
 3. An apparatus as claimed in claim 2 whereinsaid heater elements have a high bend efficiency wherein said bendefficiency is defined as the youngs modulus times the coefficient ofthermal expansion divided by the density and by the specific heatcapacity.
 4. An apparatus as claimed in claim 2 wherein said heaterelements are arranged on opposite sides of a central arm, said centralarm having a low thermal conductivity.
 5. An apparatus as claimed inclaim 4 wherein said central arm comprises substantially glass.
 6. Anapparatus as claimed in claim 2 wherein said paddle vane and saidactuator are joined at a fulcrum pivot point, said fulcrum pivot pointcomprising a thinned portion of said nozzle chamber wall.
 7. Anapparatus as claimed in claim 1 wherein said actuator includes one endfixed to a substrate and a second end containing a bifurcated tonguehaving two leaf portions on each end of said bifurcated tongue said leafportions interconnecting to a corresponding side of said paddle withsaid tongue such that, upon actuation of said actuator, one of said leafportions pulls on said paddle end.
 8. An apparatus as claimed in claim 1further comprising: a fluid supply channel connecting said nozzlechamber with a fluid supply for supplying fluid to said nozzle chambersaid connection being in a wall of said chamber substantially adjacentthe quiescent position of said paddle vane.
 9. An apparatus as claimedin claim 8 wherein said connection comprises a slot defined in the wallof said chamber, said slot having similar dimensions to across-sectional profile of said paddle vane.
 10. An apparatus as claimedin claim 1 wherein said fluid ejection apertures include a rim definedaround an outer surface thereof.
 11. A multiplicity of apparatuses asclaimed in claim 1 wherein said fluid ejection apertures are groupedtogether spatially into spaced apart rows and fluid is ejected from thefluid ejection apertures of each of said rows in phases.
 12. Amultiplicity of apparatuses as claimed in claim 11 wherein saidapparatuses are utilized for ink jet printing.
 13. A multiplicity ofapparatuses as claimed in claim 12 said nozzle chambers are furthergrouped into multiple ink colors and with each of said nozzles beingsupplied with a corresponding ink color.
 14. A method of ejecting dropsof fluid from a nozzle chamber having at least two nozzle aperturesdefined in the wall of said nozzle chambers utilizing a moveable paddlevane attached to an actuator mechanism, said method comprising the stepsof: actuating said actuator to cause said moveable paddle to move in afirst direction so as to eject drops from a first of said nozzleapertures; and actuating said actuator to cause said moveable paddle tomove in a second direction so as to eject drops from a second of saidnozzle apertures.
 15. A method as claimed in claim 14 wherein an arrayof nozzle chambers are arranged in a pagewidth print head and themoveable paddles of each nozzle chamber are driven in phase.